SY 5305-1987 General technical requirements for welded parts for petroleum drilling and production machinery products SY5305-1987 standard download decompression password: www.bzxz.net

Ministry of Petroleum Industry of the People's Republic of China Standard SY5305-87
This standard was confirmed to be valid in 1998, and this is hereby stated. Welding parts for oil drilling and production machinery products
General technical conditions
Published on April 18, 1988
Ministry of Petroleum Industry of the People's Republic of China
Implementation on June 1, 1988
Ministry of Petroleum Industry of the People's Republic of China Standard General technical conditions for welding parts for oil drilling and production machinery products SY 5305--87
This standard applies to welded structural parts of low carbon steel and ordinary low alloy steel completed by manual arc welding, submerged arc welding and gas shielded arc welding in oil drilling and production machinery. If special requirements are required, they should be indicated in the drawings or technical documents. Technical requirements
The raw materials (steel plates, steel sections and steel pipes, etc.) and welding materials (welding rods, welding wires and flux, etc.) used for welding structural parts shall comply with the following provisions in 1.1
:
Deviation name
Straightness of steel plates and flat steel within every
1000mm length
Angle steel. Straightness of channel steel I-beam and pipe
Verticality of two legs of angle steel
Inclination of filler flange of I-beam and channel
Approved by the Ministry of Petroleum Industry of the People's Republic of China on April 18, 1988
Allowable deviation
82141 f1
8 eight 14: f41-5
Straightness less than 5
Implementation on June 1, 1988
SY 5305--B7
1.1.1 The steel grade, specification and size of raw materials used for welding structural parts shall meet the requirements of the drawings. If they do not meet the requirements, they shall be substituted according to the factory material substitution system.
1.1.2 The welding rods used for welding structural parts shall comply with the provisions of GB980 "Welding rod classification and model compilation method", GB6117 "Low carbon steel welding rod", GB5118 "Low alloy steel welding rod", GB982 "Aluminum and chromium-molybdenum heat-resistant steel welding rod", GB983 "Stainless steel welding rod", GB 984 "Overlay welding rod".
1.1.3 The raw materials and welding materials used for welding structural parts shall be inspected by the technical inspection department according to their quality certificates before use. Raw materials and welding materials without brand names and quality certificates shall be inspected and identified, and their brand names and specifications shall be determined before use. 1-1.4 It is strictly forbidden to use various materials with unknown brands and not accepted by the technical inspection department. 1.2 The allowable deviations of various steel materials before cutting are shown in Table 1. 1.3 When the deformation of steel materials before cutting exceeds the allowable deviation, they must be corrected before use. There are two correction methods: cold correction and hot correction; a. Cold correction of steel should be carried out using a straightening machine or press, or manual correction can be used, but the depth of the hammer mark shall not exceed the requirements of Table 2.
Thickness, 810
Thickness, >10
On the leg or wing
On the belly
Depth of hammer mark (not more than)
b. When the deformation degree of steel is large or the equipment capacity is insufficient, hot correction can be used. During hot correction, the steel should be heated to 900~1100°C for correction (lower temperature is used for ordinary low-alloy steel), and there should be no concave and convex scars and chain marks on the surface of the steel after correction. When the temperature of the steel is between 300~500°C (blue brittle temperature) or below -25°C, no blows are allowed to the steel. c. For steel that allows local heating, its local expansion can be corrected by flame. During flame straightening, the heating temperature is usually 600~~800°C, and it should not exceed 850\C.
1.4 The templates of mass-produced parts must be made according to the material, marking and assembly procedures, and all kinds of templates should be made of thin iron sheets. 1.4.1 The production of the template must take into account the shrinkage of the structure during welding, and the size of the shrinkage is specified according to the process requirements. 1.4.2 The assembly gap of the welded structural parts is not considered in the design drawings, but it should be considered when making the template. The gap is allowed to be 1~1.5mm (Figure 1).
$Y 5305--87
1.4.3 The production of the template must also consider the cutting allowance, flame straightening shrinkage allowance and machining allowance. 1.4.4 The outer dimension deviation of the template should be within the range of 0.5~1mm. 1.4.5 The hole spacing of the marking template for drilling should meet the requirements of the drawing. If there is no tolerance requirement in the drawing, the deviation of the center distance between the two holes is ±0.5mm, and the deviation of the distance between the center line of hole 4 and the edge of the plate is ±1mm. 1.4.6: Each sample must be marked with the work number, drawing number, material section size, steel grade, and the number of parts manufactured using the sample. The sample must be inspected and qualified before use.
1.5 Before making the material, the sample should be carefully checked for deformation. 1.6 When making the material, the actual material line, allowance line, center line and bending line should be drawn, and the letters and weld codes at the joints should be noted. If the parts are assembled (or processed) on site, they should be noted according to the drawing. 1.7 Good steel should be marked with the work number, drawing number, name, part number, specification, steel grade, and number of each piece. 1.8 Steel cutting can be machine shearing or gas cutting. Gas cutting should be preferred for steel with a thickness greater than 16m. 1.9 After cutting, the edge should be perpendicular to the surface, and the inclination of the cut surface should not exceed 1:10. The deposits, burrs and unevenness on the edge should be removed.
1.10 After mechanical shearing, the surface of the cut edge is allowed to have an indentation with a depth not exceeding 1mm and a burr with a height not exceeding 0.5mm. The deviation between the mechanical shearing line and the material line shall not exceed the provisions of Table 3. t.11
Length of parts
>100~250
>250~B50
>650~1000
>1000-~1500
>1500~2000
>100-250
>250~650
>850~1000
>1000~1500
>1500~2000
>2000~3000
>3000-4000
2 The allowable difference between the gas cutting line and the material line is as follows: 1.12
a: When cutting by hand, it shall not exceed ±1.5mmb. The error should not exceed ±1.0mm when cutting automatically or semi-automatically. -
Difference (±)
18～20
1.13 Quality of gas cutting According to the provisions of JB3092 "Technical Requirements for Flame Cutting Surface Quality", defects on the cut surface of non-welding surfaces must be welded and leveled.
1.14 The dimensional deviation of welded structural parts not specified in the drawings shall be in accordance with Table 4. 1.16 Except for steel plates with a thickness greater than 16mm, steel materials with a carbon content greater than 0.27% after gas cutting, and when the curvature on both sides of the flat steel must be removed and cannot be corrected by editing, if other steel materials require edge planing after cutting, it should be noted. 3
Part size
>100~250
>250~650
>6501000
>1000~1600
>1600~2500
>2500~4000
74000-6500
>6500~100D0
Note, size deviation for holes and grooves is
+*,
SY 5305—8T
length is
sharpness,
value, depth of blind holes is*+value
1.16 After planing the steel, the straightness of the edge shall not be greater than 1/2000 of the component length, and the maximum shall not exceed 1.5mm. The difference between the planed part size and the original design size shall not exceed 1.5mm. 1.17 The size and deviation of the welding groove shall comply with the provisions of GB985 "Basic Types and Dimensions of Manual Arc Welding and Welding Joints" and GB986 "Basic Types and Dimensions of Submerged Arc Welding Joints". 1.18 When steel is formed and bent, the minimum bending radius shall be as specified in Table 5. Table 5
Outer bend of equal reverse angle steel
Inner bend of equal angle steel
Outer bend of small side of unequal angle steel
6—20Www.bzxZ.net
6—%o
20--75—820
—20-256-2626
b+206(5-)
-6+2=24(6 2a)
376-8x
25628 yuan
Outside of the large side of the unequal angle steel
Inside of the small side of the unequal angle steel
Inside of the large side of the unequal angle steel
I-beam bends along the y--y
Axis
I-beam bends along the - axis
Channel steel bends along the - axis
SY 5305—87
Continued Table 5
Rrala=
-y-7B-8y
=25B-26
b+x6(6-x0)
5+x=24（6—）
--B+.-6(B-)
2×0+14
-B+V.=24 (By.)
—125
Channel steel is bent by—ye
Channel steel is bent by y—y axis
Circular steel is bent
Flat steel is bent
SY 5305--87
Continued Table 5
When 8510
Raln=&
R...a- 3α
R..m=12α
20576-820
20=25h—26zm
-5+z~6(b-20)
6+2.=24 (6—20)
1.19When hot bending is adopted for materials, the steel shall be heated to 900-~1100°C. When the bending is completed, the temperature shall not be lower than 700°C. For ordinary low alloy steel, slow cooling shall be taken.
1.20The dimensional deviation of the simplified body after bending shall be in accordance with the provisions of Table 6. When the pipe is bent, it should be hot-bent with sand, and the heating temperature is 800~1100°C. The temperature during the bending process shall not be lower than 700°C. When using medium-frequency induction heating or flame heating pipe bending machine, sand can be omitted. Cold bending should be carried out on a special pipe bending machine, and manual cold bending can be used for non-pressure-bearing pipes.
1.22 The minimum bending radius of the pipe shall be as specified in Table 7. 1.23 The bending radius deviation, roundness deviation and allowable corrugation depth of the pipe shall be as specified in Table 8. Welded structural parts must be inspected and qualified before assembly. When assembling welded structural parts, the dimensions indicated on the drawing must be maintained. For parts with unqualified dimensions, forced assembly is prohibited. 1.25 When assembling welded structures, the deviation of the mutual position of two weldments (or weld edges) shall comply with the following provisions: 1.25.1 When assembling butt joints, the allowable deviation shall be as specified in Table 9. 1.25.2 When assembling lap joints, the lap width deviation range should be -2 to +10 mm (Figure 2). 1.25.3 When assembling structures with complex cross-sections (Figure 3), the allowable deviation shall be as specified in Table 10. 6
SY 5305—87
1000-1500
>15002000
2000-2500
>2500-9000
Bending process
Welded steel pipe
Seamless steel pipe
Outer diameter of pipe
Any value
Any value
>20～35
>33~60
>60~140
When the wall thickness of the cylinder is the following
value of cylindricity| The bending radius L is the shortest straight tube length at the tube end, generally = 2d, and the ear should be greater than 45. The deviation of the radius R. The roundness deviation at the bending radius R-75~125. R=160~300. IR=100. R=500~1000. R>1000. The wave effect SY at the bend 5305-87
Steel plate thickness
Allowable value of the lower deviation
5～12
Steel number
SY 5305-87
Not more than 1.5~2,P
Not more than 1.0~1.5
Not more than 0.8～1.0
Not more than 0.015
And not more than 5
When assembling various types of pipelines, the displacement between the pipe walls (Figure 4) is allowed to be within 10% of the pipe wall thickness, but shall not exceed 1.5mm. Butt joints of steel plates of different thicknesses shall comply with the provisions of GB985 and GB986. 1.25.5
1.26 The tack weld used for welding parts during assembly shall be part of the subsequent weld and meet the following requirements: 1.26.1 Tack welds must be performed by welders who have passed the examination. 9
SY 5305--8
1.26.2 Tack welds and formal welding use the same brand of welding rods, and their diameter specifications should be one level smaller. 1.26.3 The size of the tack welds shall be selected according to Table 11. The size and number of tack welds can be appropriately increased in important parts, but the height of the welds shall not exceed the height of the formal welds.
Weldment thickness
Tack weld height
3~～6
1.26.4 Weldments that need to be preheated should also be preheated during tack welding. Weld length
50~100
100200
100~300
1.26.5 For important welded structural parts, tack welding should be performed on the back side if possible: after the front side is welded, the tack weld on the back side should be removed before welding the back side.
1.26.6 Tack welding shall not be performed at the intersection of welds and at locations with sharp changes. 1.26.7 Tack welds with cracks must be removed and re-welded, and the arc pits must be filled. 1.27 Cracks and other defects on the edge of the joint structure that exceed the specified deviation limit should be repaired with excellent welding rods after inspection and approval by the technical inspection department.
1.28 Assembled welded structural parts can only be welded after passing the inspection. 1.29 Welders should undergo special training and pass the examination before they can be engaged in welding work. 1.30 Before welding, remove the dirt in the welding area and within 20mm (30mm from the weld edge), such as rust, scale, oil, burrs, slag, paint, etc.
1.31 When welding in the open air, protective measures should be taken in case of rain, snow, strong wind or heavy fog, otherwise welding shall not be carried out. 1.32 The following conditions should be observed when welding below 0°C: a. Ensure that the weld can shrink freely during welding b. Do not hit the welded structure with a heavy hammer:
e. Preheat before welding. The preheating temperature required for ordinary low-alloy steel is in accordance with Table 12. 10
Thickness, mm
8>18~24
8>24~40
Defect name
(1) Longitudinal
(2) Transverse
(3)
Weld discontinuity on parent metal
Arc crater-shaped defects exposed
SY 530587
Preheat below 10*C
Preheat below 5'C
Spot heat below o'C
Uniform heating
100--150'C
100~150*C
100~150°C
100~150'C
Defects and dimensional tolerances
The length of the undercut shall not exceed 15% of the length of the weld, and its depth shall not exceed the following provisions:
8≤10mm, 218=0.5mm
8>10mm, 48=1mm
8>40mm, 28=1.5mm
Not allowed
Not allowed
Not allowed
Allowed=24 (By.)
—125
Channel steel is bent by—ye
Channel steel is bent in y—y axis
Circular steel is bent
Flat steel is bent
SY 5305--87
Continued Table 5
When 8510
Raln=&
R...a- 3α
R..m=12α
20576-820
20=25h—26zm
-5+z~6(b-20)
6+2.=24 (6—20)
1.19 When hot bending is used, the steel should be heated to 900-~1100°C. When the bending is completed, the temperature shall not be lower than 700°C. For ordinary low-alloy steel, slow cooling should be taken.
1.20 The dimensional deviation of the bent tube shall be in accordance with the provisions of Table 6. When the tube is bent, it shall be hot-bent with sand, and the heating temperature shall be 800~1100°C. The temperature shall not be lower than 700°C during the bending process. When medium-frequency induction heating or flame heating tube bending machine is used, sand can be omitted. Cold bending should be carried out on a special tube bending machine. For non-pressure-bearing tubes, manual cold bending can be used.
1.22 The minimum bending radius of the tube shall be in accordance with the provisions of Table 7. 1.23 The bending radius deviation, roundness deviation and allowable corrugation depth of the tube shall be in accordance with the provisions of Table 8. Welded structural parts shall be inspected and qualified before assembly. When assembling welded structural parts, the dimensions indicated on the drawing must be maintained. For parts with unqualified dimensions, forced assembly is prohibited. 1.25 When assembling welded structures, the deviation of the mutual position of two weldments (or weld edges) shall comply with the following provisions: 1.25.1 When assembling butt joints, the allowable deviation shall be in accordance with Table 9. 1.25.2 When assembling lap joints, the deviation range of the lap width shall be -2 to +10 mm (Figure 2). 1.25.3 When assembling structures with complex cross-sections (Figure 3), the allowable deviation shall be in accordance with Table 10. 6
SY 5305—87
1000-1500
>15002000
2000-2500
>2500-9000
Bending process
Welded steel pipe
Seamless steel pipe
Outer diameter of pipe
Any value
Any value
>20～35
>33~60
>60~140
When the wall thickness of the cylinder is the following
value of cylindricity| The bending radius L is the shortest straight tube length at the tube end, generally = 2d, and the ear should be greater than 45. The deviation of the radius R. The roundness deviation at the bending radius R-75~125. R=160~300. IR=100. R=500~1000. R>1000. The wave effect SY at the bend 5305-87
Steel plate thickness
Allowable value of the lower deviation
5～12
Steel number
SY 5305-87
Not more than 1.5~2,P
Not more than 1.0~1.5
Not more than 0.8～1.0
Not more than 0.015
And not more than 5
When assembling various types of pipelines, the displacement between the pipe walls (Figure 4) is allowed to be within 10% of the pipe wall thickness, but shall not exceed 1.5mm. Butt joints of steel plates of different thicknesses shall comply with the provisions of GB985 and GB986. 1.25.5
1.26 The tack weld used for welding parts during assembly shall be part of the subsequent weld and meet the following requirements: 1.26.1 Tack welds must be performed by welders who have passed the examination. 9
SY 5305--8
1.26.2 Tack welds and formal welding use the same brand of welding rods, and their diameter specifications should be one level smaller. 1.26.3 The size of the tack welds shall be selected according to Table 11. The size and number of tack welds can be appropriately increased in important parts, but the height of the welds shall not exceed the height of the formal welds.
Weldment thickness
Tack weld height
3~～6
1.26.4 Weldments that need to be preheated should also be preheated during tack welding. Weld length
50~100
100200
100~300
1.26.5 For important welded structural parts, tack welding should be performed on the back side if possible: after the front side is welded, the tack weld on the back side should be removed before welding the back side.
1.26.6 Tack welding shall not be performed at the intersection of welds and at locations with sharp changes. 1.26.7 Tack welds with cracks must be removed and re-welded, and the arc pits must be filled. 1.27 Cracks and other defects on the edge of the joint structure that exceed the specified deviation limit should be repaired with excellent welding rods after inspection and approval by the technical inspection department.
1.28 Assembled welded structural parts can only be welded after passing the inspection. 1.29 Welders should undergo special training and pass the examination before they can be engaged in welding work. 1.30 Before welding, remove the dirt in the welding area and within 20mm (30mm from the weld edge), such as rust, scale, oil, burrs, slag, paint, etc.
1.31 When welding in the open air, protective measures should be taken in case of rain, snow, strong wind or heavy fog, otherwise welding shall not be carried out. 1.32 The following conditions should be observed when welding below 0°C: a. Ensure that the weld can shrink freely during welding b. Do not hit the welded structure with a heavy hammer:
e. Preheat before welding. The preheating temperature required for ordinary low-alloy steel is in accordance with Table 12. 10
Thickness, mm
8>18~24
8>24~40
Defect name
(1) Longitudinal
(2) Transverse
(3)
Weld discontinuity on parent metal
Arc crater-shaped defects exposed
SY 530587
Preheat below 10*C
Preheat below 5'C
Spot heat below o'C
Uniform heating
100--150'C
100~150*C
100~150°C
100~150'C
Defects and dimensional tolerances
The length of the undercut shall not exceed 15% of the length of the weld, and its depth shall not exceed the following provisions:
8≤10mm, 218=0.5mm
8>10mm, 48=1mm
8>40mm, 28=1.5mm
Not allowed
Not allowed
Not allowed
Allowed=24 (By.)
—125
Channel steel is bent by—ye
Channel steel is bent in y—y axis
Circular steel is bent
Flat steel is bent
SY 5305--87
Continued Table 5
When 8510
Raln=&
R...a- 3α
R..m=12α
20576-820
20=25h—26zm
-5+z~6(b-20)
6+2.=24 (6—20)
1.19 When hot bending is used, the steel should be heated to 900-~1100°C. When the bending is completed, the temperature shall not be lower than 700°C. For ordinary low-alloy steel, slow cooling should be taken.
1.20 The dimensional deviation of the bent tube shall be in accordance with the provisions of Table 6. When the tube is bent, it shall be hot-bent with sand, and the heating temperature shall be 800~1100°C. The temperature shall not be lower than 700°C during the bending process. When medium-frequency induction heating or flame heating tube bending machine is used, sand can be omitted. Cold bending should be carried out on a special tube bending machine. For non-pressure-bearing tubes, manual cold bending can be used.
1.22 The minimum bending radius of the tube shall be in accordance with the provisions of Table 7. 1.23 The bending radius deviation, roundness deviation and allowable corrugation depth of the tube shall be in accordance with the provisions of Table 8. Welded structural parts shall be inspected and qualified before assembly. When assembling welded structural parts, the dimensions indicated on the drawing must be maintained. For parts with unqualified dimensions, forced assembly is prohibited. 1.25 When assembling welded structures, the deviation of the mutual position of two weldments (or weld edges) shall comply with the following provisions: 1.25.1 When assembling butt joints, the allowable deviation shall be in accordance with Table 9. 1.25.2 When assembling lap joints, the deviation range of the lap width shall be -2 to +10 mm (Figure 2). 1.25.3 When assembling structures with complex cross-sections (Figure 3), the allowable deviation shall be in accordance with Table 10. 6
SY 5305—87
1000-1500
>15002000
2000-2500
>2500-9000
Bending process
Welded steel pipe
Seamless steel pipe
Outer diameter of pipe
Any value
Any value
>20～35
>33~60
>60~140
When the wall thickness of the cylinder is the following
value of cylindricity| The bending radius L is the shortest straight tube length at the tube end, generally = 2d, and the ear should be greater than 45. The deviation of the radius R. The roundness deviation at the bending radius R-75~125. R=160~300. IR=100. R=500~1000. R>1000. The wave effect SY at the bend 5305-87
Steel plate thickness
Allowable value of the lower deviation
5～12
Steel number
SY 5305-87
Not more than 1.5~2,P
Not more than 1.0~1.5
Not more than 0.8～1.0
Not more than 0.015
And not more than 5
When assembling various types of pipelines, the displacement between the pipe walls (Figure 4) is allowed to be within 10% of the pipe wall thickness, but shall not exceed 1.5mm. Butt joints of steel plates of different thicknesses shall comply with the provisions of GB985 and GB986. 1.25.5
1.26 The tack weld used for welding parts during assembly shall be part of the subsequent weld and meet the following requirements: 1.26.1 Tack welds must be performed by welders who have passed the examination. 9
SY 5305--8
1.26.2 Tack welds and formal welding use the same brand of welding rods, and their diameter specifications should be one level smaller. 1.26.3 The size of the tack welds shall be selected according to Table 11. The size and number of tack welds can be appropriately increased in important parts, but the height of the welds shall not exceed the height of the formal welds.
Weldment thickness
Tack weld height
3~～6
1.26.4 Weldments that need to be preheated should also be preheated during tack welding. Weld length
50~100
100200
100~300
1.26.5 For important welded structural parts, tack welding should be performed on the back side if possible: after the front side is welded, the tack weld on the back side should be removed before welding the back side.
1.26.6 Tack welding shall not be performed at the intersection of welds and at locations with sharp changes. 1.26.7 Tack welds with cracks must be removed and re-welded, and the arc pits must be filled. 1.27 Cracks and other defects on the edge of the joint structure that exceed the specified deviation limit should be repaired with excellent welding rods after inspection and approval by the technical inspection department.
1.28 Assembled welded structural parts can only be welded after passing the inspection. 1.29 Welders should undergo special training and pass the examination before they can be engaged in welding work. 1.30 Before welding, remove the dirt in the welding area and within 20mm (30mm from the weld edge), such as rust, scale, oil, burrs, slag, paint, etc.
1.31 When welding in the open air, protective measures should be taken in case of rain, snow, strong wind or heavy fog, otherwise welding shall not be carried out. 1.32 The following conditions should be observed when welding below 0°C: a. Ensure that the weld can shrink freely during welding b. Do not hit the welded structure with a heavy hammer:
e. Preheat before welding. The preheating temperature required for ordinary low-alloy steel is in accordance with Table 12. 10
Thickness, mm
8>18~24
8>24~40
Defect name
(1) Longitudinal
(2) Transverse
(3)
Weld discontinuity on parent metal
Arc crater-shaped defects exposed
SY 530587
Preheat below 10*C
Preheat below 5'C
Spot heat below o'C
Uniform heating
100--150'C
100~150*C
100~150°C
100~150'C
Defects and dimensional tolerances
The length of the undercut shall not exceed 15% of the length of the weld, and its depth shall not exceed the following provisions:
8≤10mm, 218=0.5mm
8>10mm, 48=1mm
8>40mm, 28=1.5mm
Not allowed
Not allowed
Not allowed
Allowed25 When assembling welded structures, the deviation of the mutual position of two weldments (or weld edges) shall comply with the following provisions: 1.25.1 When assembling butt joints, the allowable deviation shall be in accordance with Table 9. 1.25.2 When assembling lap joints, the deviation range of the lap width shall be -2 to +10 mm (Figure 2). 1.25.3 When assembling structures with complex cross-sections (Figure 3), the allowable deviation shall be in accordance with Table 10. 6
SY 5305—87
1000-1500
>15002000
2000-2500
>2500-9000
Bending process
Welded steel pipe
Seamless steel pipe
Outer diameter of pipe
Any value
Any value
>20～35
>33~60
>60~140
When the wall thickness of the cylinder is the following
value of cylindricity| The bending radius L is the shortest straight tube length at the tube end, generally = 2d, and the ear should be greater than 45. The deviation of the radius R. The roundness deviation at the bending radius R-75~125. R=160~300. IR=100. R=500~1000. R>1000. The wave effect SY at the bend 5305-87
Steel plate thickness
Allowable value of the lower deviation
5～12
Steel number
SY 5305-87
Not more than 1.5~2,P
Not more than 1.0~1.5
Not more than 0.8～1.0
Not more than 0.015
And not more than 5
When assembling various types of pipelines, the displacement between the pipe walls (Figure 4) is allowed to be within 10% of the pipe wall thickness, but shall not exceed 1.5mm. Butt joints of steel plates of different thicknesses shall comply with the provisions of GB985 and GB986. 1.25.5
1.26 The tack weld used for welding parts during assembly shall be part of the subsequent weld and meet the following requirements: 1.26.1 Tack welds must be performed by welders who have passed the examination. 9
SY 5305--8
1.26.2 Tack welds and formal welding use the same brand of welding rods, and their diameter specifications should be one level smaller. 1.26.3 The size of the tack welds shall be selected according to Table 11. The size and number of tack welds can be appropriately increased in important parts, but the height of the welds shall not exceed the height of the formal welds.
Weldment thickness
Tack weld height
3~～6
1.26.4 Weldments that need to be preheated should also be preheated during tack welding. Weld length
50~100
100200
100~300
1.26.5 For important welded structural parts, tack welding should be performed on the back side if possible: after the front side is welded, the tack weld on the back side should be removed before welding the back side.
1.26.6 Tack welding shall not be performed at the intersection of welds and at locations with sharp changes. 1.26.7 Tack welds with cracks must be removed and re-welded, and the arc pits must be filled. 1.27 Cracks and other defects on the edge of the joint structure that exceed the specified deviation limit should be repaired with excellent welding rods after inspection and approval by the technical inspection department.
1.28 Assembled welded structural parts can only be welded after passing the inspection. 1.29 Welders should undergo special training and pass the examination before they can be engaged in welding work. 1.30 Before welding, remove the dirt in the welding area and within 20mm (30mm from the weld edge), such as rust, scale, oil, burrs, slag, paint, etc.
1.31 When welding in the open air, protective measures should be taken in case of rain, snow, strong wind or heavy fog, otherwise welding shall not be carried out. 1.32 The following conditions should be observed when welding below 0°C: a. Ensure that the weld can shrink freely during welding b. Do not hit the welded structure with a heavy hammer:
e. Preheat before welding. The preheating temperature required for ordinary low-alloy steel is in accordance with Table 12. 10
Thickness, mm
8>18~24
8>24~40
Defect name
(1) Longitudinal
(2) Transverse
(3)
Weld discontinuity on parent metal
Arc crater-shaped defects exposed
SY 530587
Preheat below 10*C
Preheat below 5'C
Spot heat below o'C
Uniform heating
100--150'C
100~150*C
100~150°C
100~150'C
Defects and dimensional tolerances
The length of the undercut shall not exceed 15% of the length of the weld, and its depth shall not exceed the following provisions:
8≤10mm, 218=0.5mm
8>10mm, 48=1mm
8>40mm, 28=1.5mm
Not allowed
Not allowed
Not allowed
Allowed25 When assembling welded structures, the deviation of the mutual position of two weldments (or weld edges) shall comply with the following provisions: 1.25.1 When assembling butt joints, the allowable deviation shall be in accordance with Table 9. 1.25.2 When assembling lap joints, the deviation range of the lap width shall be -2 to +10 mm (Figure 2). 1.25.3 When assembling structures with complex cross-sections (Figure 3), the allowable deviation shall be in accordance with Table 10. 6
SY 5305—87
1000-1500
>15002000
2000-2500
>2500-9000
Bending process
Welded steel pipe
Seamless steel pipe
Outer diameter of pipe
Any value
Any value
>20～35
>33~60
>60~140
When the wall thickness of the cylinder is the following
value of cylindricity| The bending radius L is the shortest straight tube length at the tube end, generally = 2d, and the ear should be greater than 45. The deviation of the radius R. The roundness deviation at the bending radius R-75~125. R=160~300. IR=100. R=500~1000. R>1000. The wave effect SY at the bend 5305-87
Steel plate thickness
Allowable value of the lower deviation
5～12
Steel number
SY 5305-87
Not more than 1.5~2,P
Not more than 1.0~1.5
Not more than 0.8～1.0
Not more than 0.015
And not more than 5
When assembling various types of pipelines, the displacement between the pipe walls (Figure 4) is allowed to be within 10% of the pipe wall thickness, but shall not exceed 1.5mm. Butt joints of steel plates of different thicknesses shall comply with the provisions of GB985 and GB986. 1.25.5
1.26 The tack weld used for welding parts during assembly shall be part of the subsequent weld and meet the following requirements: 1.26.1 Tack welds must be performed by welders who have passed the examination. 9
SY 5305--8
1.26.2 Tack welds and formal welding use the same brand of welding rods, and their diameter specifications should be one level smaller. 1.26.3 The size of the tack welds shall be selected according to Table 11. The size and number of tack welds can be appropriately increased in important parts, but the height of the welds shall not exceed the height of the formal welds.
Weldment thickness
Tack weld height
3~～6
1.26.4 Weldments that need to be preheated should also be preheated during tack welding. Weld length
50~100
100200
100~300
1.26.5 For important welded structural parts, tack welding should be performed on the back side if possible: after the front side is welded, the tack weld on the back side should be removed before welding the back side.
1.26.6 Tack welding shall not be performed at the intersection of welds and at locations with sharp changes. 1.26.7 Tack welds with cracks must be removed and re-welded, and the arc pits must be filled. 1.27 Cracks and other defects on the edge of the joint structure that exceed the specified deviation limit should be repaired with excellent welding rods after inspection and approval by the technical inspection department.
1.28 Assembled welded structural parts can only be welded after passing the inspection. 1.29 Welders should undergo special training and pass the examination before they can be engaged in welding work. 1.30 Before welding, remove the dirt in the welding area and within 20mm (30mm from the weld edge), such as rust, scale, oil, burrs, slag, paint, etc.
1.31 When welding in the open air, protective measures should be taken in case of rain, snow, strong wind or heavy fog, otherwise welding shall not be carried out. 1.32 The following conditions should be observed when welding below 0°C: a. Ensure that the weld can shrink freely during welding b. Do not hit the welded structure with a heavy hammer:
e. Preheat before welding. The preheating temperature required for ordinary low-alloy steel is in accordance with Table 12. 10
Thickness, mm
8>18~24
8>24~40
Defect name
(1) Longitudinal
(2) Transverse
(3)
Weld discontinuity on parent metal
Arc crater-shaped defects exposed
SY 530587
Preheat below 10*C
Preheat below 5'C
Spot heat below o'C
Uniform heating
100--150'C
100~150*C
100~150°C
100~150'C
Defects and dimensional tolerances
The length of the undercut shall not exceed 15% of the length of the weld, and its depth shall not exceed the following provisions:
8≤10mm, 218=0.5mm
8>10mm, 48=1mm
8>40mm, 28=1.5mm
Not allowed
Not allowed
Not allowed
Allowed5 For important welded structural parts, tack welding should be performed on the back side if possible: after the front side is welded, the tack weld on the back side should be removed before welding the back side.
1.26.6 Tack welding shall not be performed at the intersection of welds and at locations with sharp changes. 1.26.7 If there are cracks in the tack weld, they must be removed and re-welded, and the arc pit must be filled. 1.27 Cracks and other defects on the edge of the joint structure that exceed the specified deviation limit should be repaired with high-quality welding rods after inspection and approval by the technical inspection department.
1.28 Assembled welded structural parts can only be welded after passing the inspection. 1.29 Welders should receive special training and pass the examination before they can perform welding work. 1.30 Before welding, the welding glass area and dirt within 20mm (30mm buried) from the edge of the weld should be removed, such as rust, scale, oil, burrs, slag, paint, etc.
1.31 When welding in the open air, protective measures should be taken in case of rain, snow, strong wind or heavy fog, otherwise welding shall not be carried out. 1.32 When welding below 0°C, the following conditions should be followed: a. Ensure that the weld can shrink freely during welding b. Do not hit the welded structure with a heavy hammer:
e. Preheat before welding. For ordinary low-alloy steel, the required preheating temperature is in accordance with Table 12. 10
Thickness, mm
8>18~24
8>24~40
Defect name
(1) Vertical
(2) Horizontal
(3)
Weld discontinuity on the parent metal
Defects in the shape of arc pits
SY 530587
Preheat below 10*C
Preheat below 5'C
Spot heat below o'C
Uniform heating
100--150'C
100~150*C
100~150°C
100~150'C
Defects and dimensional tolerances
The length of the undercut shall not exceed 15% of the length of the weld, and its depth shall not exceed the following provisions:
8≤10mm, 218=0.5mm
8>10mm, 48=1mm
8>40mm, 28=1.5mm
Not allowed
Not allowed
Not allowed
Allowed5 For important welded structural parts, tack welding should be performed on the back side if possible: after the front side is welded, the tack weld on the back side should be removed before welding the back side.
1.26.6 Tack welding shall not be performed at the intersection of welds and at locations with sharp changes. 1.26.7 If there are cracks in the tack weld, they must be removed and re-welded, and the arc pit must be filled. 1.27 Cracks and other defects on the edge of the joint structure that exceed the specified deviation limit should be repaired with high-quality welding rods after inspection and approval by the technical inspection department.
1.28 Assembled welded structural parts can only be welded after passing the inspection. 1.29 Welders should receive special training and pass the examination before they can perform welding work. 1.30 Before welding, the welding glass area and dirt within 20mm (30mm buried) from the edge of the weld should be removed, such as rust, scale, oil, burrs, slag, paint, etc.
1.31 When welding in the open air, protective measures should be taken in case of rain, snow, strong wind or heavy fog, otherwise welding shall not be carried out. 1.32 When welding below 0°C, the following conditions should be followed: a. Ensure that the weld can shrink freely during welding b. Do not hit the welded structure with a heavy hammer:
e. Preheat before welding. For ordinary low-alloy steel, the required preheating temperature is in accordance with Table 12. 10
Thickness, mm
8>18~24
8>24~40
Defect name
(1) Vertical
(2) Horizontal
(3)
Weld discontinuity on the parent metal
Defects in the shape of arc pits
SY 530587
Preheat below 10*C
Preheat below 5'C
Spot heat below o'C
Uniform heating
100--150'C
100~150*C
100~150°C
100~150'C
Defects and dimensional tolerances
The length of the undercut shall not exceed 15% of the length of the weld, and its depth shall not exceed the following provisions:
8≤10mm, 218=0.5mm
8>10mm, 48=1mm
8>40mm, 28=1.5mm
Not allowed
Not allowed
Not allowed
Allowed
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