This standard specifies the technical requirements, test methods, inspection rules and marking, packaging, transportation, storage, etc. of welded parts in engineering machinery products. This standard is applicable to welded parts of manual arc welding, submerged arc welding and gas shielded welding. JB/T 5943-1991 General Technical Conditions for Welded Parts of Engineering Machinery JB/T5943-1991 Standard download decompression password: www.bzxz.net

Machinery Industry Standard of the People's Republic of China
JB/T5943-1991
Engineering machinery
General technical conditions for welded parts
Issued on December 12, 1991
Implementation by the Ministry of Machinery and Electronics Industry of the People's Republic of China on July 1, 1992
Machinery Industry Standard of the People's Republic of China
Engineering machinery
General technical conditions for welded parts
1 Subject content and scope of application
JB/T5943-1991
This standard specifies the technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of welded parts in engineering machinery products.
This standard applies to welds made by manual arc welding, submerged arc welding and gas shielded welding. 2 Reference standards
GB1804
GB2650
GB2651
GB2652
GB2653
GB2654
GB2655
GB2656
GB2828
GB3323
GB9448
3 Technical requirements
Basic forms and sizes of weld grooves for gas welding, manual arc welding and gas shielded welding Basic forms and sizes of weld grooves for submerged arc welding Form and size tolerance and fit
Welded joint impact test method
Welded joint tensile test method
Weld and deposited metal tensile test method
Welded joint bending and flattening test method
Welded joint and cladding metal hardness test method Welded joint strain aging sensitivity test method Weld metal and welded joint fatigue test method Batch inspection counting sampling procedure and sampling table (applicable to continuous batch inspection) Steel fusion welding butt joint radiography and quality classification Welding and cutting safety
3.1 The manufacture of welded parts shall comply with the product drawings, technical documents and this standard approved through the prescribed procedures. 3.2 Welded parts materials and welding materials
3.2.1 The steel grade, specification and size of the materials used for welded parts shall comply with the requirements of the drawings. 3.2.2 The materials (steel plates, steel sections, etc.) and welding materials (welding rods, welding wires, welding flux, etc.) used for welded parts shall comply with the material standards when entering the factory and shall be used only after passing the inspection.
3.2.3 Welding materials and welding materials without brand names and certificates of conformity must be inspected and identified, and can only be used after being confirmed as qualified. 3.2.4 The shape deviation of steel before cutting should comply with the relevant national standards and metallurgical industry standards; otherwise, it should be corrected to meet the requirements. During correction, the depth of the scar: steel plate should be less than 0.5mm, and steel should be less than 1mm. 3.3 Limit deviation of the uninjected tolerance size and uninjected shape and position tolerance of welded parts before assembly after cutting 3.3.1 Limit deviation of part size.
3.3.1.1 The limit deviation of the size of mechanically cut plate parts should comply with the provisions of Table 1. The limit deviation of the size of manually gas-cut plates and profiles (angle steel, I-beam, channel steel, etc., approved by the Ministry of Machinery and Electronics Industry on December 12, 1991 and implemented on July 1, 1992
JB/T5943-1991
) shall comply with the requirements of Table 2. Table 1
This size
≤500
>500~1000
>1000~2500
>2500~4000
>4000~6300
>6300~10000
>10000
Basic size|| tt||>500~1000
>1000~2500
>2500~4000
>4000~63 00
>6300~10000
>10000
Plate thickness
Profile height
≤100
Plate thickness
>10~20
Plate thickness
>10~20
Profile height
>100~200
Plate thickness
>20~30
Profile height
>200~300
±3: 5
The limit deviation of the diameter of the gas-cut hole (disc) shall comply with the following provisions 3. 3. 1.2
Plate thickness
Profile height
When the plate thickness is less than or equal to 18mm, the limit deviation of the diameter of the gas-cut hole (disc) shall comply with the provisions of H16 (h16) in GB1804; when the plate thickness is greater than 18-30mm, the limit deviation of the diameter of the gas-cut hole (disc) shall be enlarged by 0.5mm according to H16 (h16); when the plate thickness is greater than 30mm, the limit deviation of the diameter of the gas-cut hole (disc) shall be enlarged by 1mm according to H16 (h16). 3.3.1.3 The dimensional tolerance of curved parts formed by bending shall comply with the provisions of Table 3. 3.3.1.4 The limit deviation of the dimensional of planed parts shall comply with the provisions of Table 4. 3.3.2 Part geometric tolerances
The straightness and flatness tolerances of the surface of sheet metal parts shall comply with the requirements of Table 5. Straightness shall be measured over the entire length of the measured surface. Table 3
Plate thickness≤6
≤250
>250~500
>500~1000
>1000~2000
Sample length
Width≤250
Width>250
Plate thickness>6~18
Width≤250
Width>250
Plate thickness>18
Width≤250
Width>250
3. 3 2. 3
3mm.
Edge planing length
≤1000
>1000~2500
Straightness (t)
Measured surface length
≤1000
JB/T5943—1991
Flatness
Within any 1000 length
But not greater than 5.0
But not greater than 5.0
Limit deviation of width dimension
Tolerance zone diagram
Straightness
Flatness
The straightness, flatness and perpendicularity tolerances of profile parts shall comply with the provisions of Table 6, and the distortion error shall comply with the provisions of Table 7. The straightness tolerance of the edge of the plate parts after cutting or scraping by the wind pin is 2/1000 of the edge shuttle length, but shall not be greater than that of the plate parts after planing. The straightness tolerance of the edge is 0.5/1000 of the edge length, but shall not be greater than 1.5mm (see Figure 1). Table 6
Flatness
Tolerance()
L≤1000
L>1000
But the angle steel shall not be greater than 6,
I-beam and channel steel shall not be greater than 4
Within any 1000 length
The edge width must be straight
but shall not be greater than 2 (unequal sides
angle steel is calculated according to the width of the long side)
Tolerance zone brief
Profile height
≤100
Profile length
≤2000
JB/T5943-1991
Twist error
but shall not be greater than 3
but shall not be greater than 3
The perpendicularity of the cutting edges of the plate and profile parts to the surface shall not be greater than that specified in Table 8. L
Part thickness
>10~18
>18~30
>30~50
Verticality
LLength of one side tStraightness
3.3.2.5The verticality and parallelism between the edges of sheet metal parts shall not be greater than half of the tolerance of the corresponding size (see Figure 2). LAL
1SAL/2
(SAL/2
3.3.2.6The verticality of the cut section of the profile part to its surface and the parallelism of the cut surface of the profile part shall not be greater than half of the dimensional tolerance between the cut sections of the profile part (see Figure 3). 3.3.2.7
The limit deviation, roundness and bend angle of the size of the cylindrical parts formed by bending shall comply with the provisions of Table 9. Outer diameter D
≤500
>500~1000
>1000~1600
>1600~2000
>2000~2500
>2500~3150
3.3.3 Cutting requirements
Limit deviation
Roundness tolerance
JB/T5943-1991
t5A1/2
3.3.3.1 The edges of the parts cut by machinery shall not have a height of more than 0.5mm and a depth of more than 1mm. mm
3.3.3.2 There should be no slag and iron oxide scale on the gas-cut edges of parts, and the depth of the notch should comply with the provisions of Table 10. When gas cutting circles and arcs, the depth of the notch is allowed to increase by 0.5mm. The cumulative length of the notch shall not exceed 10% of the gas-cut edge length. Oxide scale is allowed to exist in the notch. Table 10bzxz.net
Thickness of the part
>20~30
>30~50
3.4 ​​Requirements before welding
Notch depth (t)
Manual gas cutting
Not more than
Gas cutting machine gas cutting
All parts must be inspected and qualified before they can be assembled. The depth of the local notch
is not greater than
Tolerance zone diagram
3.4.2 The weld groove form and size and weld gap of welded parts shall comply with the relevant provisions of GB985 and GB986. The unevenness of the weld image over its entire length shall be within the gap tolerance range. 3.4.3
When welding parts, the mutual position offset of the two welds (or weld edges): steel plate butt joint (see Figure 4);
steel butt joint (see Figure 5);
When butt joints are installed, they shall comply with the provisions of Table 11; when I-beams and box frames are installed, they shall comply with the provisions of Table 12; when installing structures with complex cross-sections, they shall comply with the provisions of Table 13; when installing pipelines, the offset between pipe walls (see Figure 6). 6
JB/T59431991
Plate thickness ≤6mm, <1mm;
Plate thickness>6mm, <2mm
Steel height h≤180mm, t<1mm
Key height h>180~360mm, t<1.5mmSteel height h>360~630mm, t<2mm
Manual electric welding
When the pipe wall thickness is ≤5mm.t≤0.5mm!
When the wall thickness is 8>5mm, ≤0.18. But not more than 2mm Figure 6
Warm plate offset
Benefit plate tilt
Web plate tilt
Web plate distance
Cover plate jaw tilt
Frame torsion
JB/T5943-1991
But not more than 2
500≤1.5
h>500≤2.0
But not more than 2
L≤2500
L> 2500~5000
L>5000
Height of steel
≤100
>100~240
JB/T5943—1991
B≤1000
B>1000
Before welding, the rust, oil, paint, dust and other dirt on the surface of the welded structure within a certain range from the edge of the weld (not less than 10mm for manual welding and not less than 20mm for submerged arc welding) must be removed, and moisture must be removed. 3.5 Welding requirements
Welding work should be carried out after the assembly inspection is qualified. 3.5.1
The welding rods and welding specifications used for positioning welding during assembly and the requirements for welders should be the same as those for formal welding. The welding process of new steel grades, new welding rods and welding wires used for the first time must be tested before formal welding. Only after the evaluation is qualified can welding be carried out.
3.5.4 It is prohibited to strike an arc in the non-weld area, and it is not allowed to strike an arc at the end of the weld. 3.5.5 Welding operations should be in accordance with the relevant provisions of GB9448. 3.6 Post-weld requirements
The limit deviation of the non-machined surface of the welded part without tolerance dimensions shall comply with the provisions of Table 14. Table 14
Basic size
≤120
>120~315
>315~630
>630~1000
>1000~1600
>1600~2500
Limit deviation
Basic size
>2500~4000
>40006300
>6300~10600
>10000~16000
>16 000~25000
>25000~40000
Limit Deviation
3.6.2 The limit deviation of the unnoted tolerance dimension of the machined surface of the welded part shall not exceed 2/3 of the machining allowance, and a machining allowance of not less than 2mm shall be ensured
3.6.3 The unnoted tolerance value of the straightness of the welded part plane shall not exceed 1.5mm within a length of 1000mm; it shall not exceed 1.5/1000 of the total length, and shall not exceed 8mm at most (50% can be relaxed for thin plate welded parts less than 3mm). 3.6.4 The unnoted tolerance value of the flatness of the welded part plane shall comply with the provisions of Table 15 (50% can be relaxed for thin plate welded parts less than 3mm). Table 15
Basic dimensions
Basic dimensions
≤120
>2500~4000
>120~315
>4000~6300
>315~630
>6300~1000
>630~1000
>10000~16000
>1000~2500
>16000~25000
JB/T5943—1991
3.6.5 The roundness tolerance value of the cylindrical and conical surfaces of weldments without indication shall be within the half of its diameter tolerance. 3.6.6 The unindicated tolerance value of the coaxiality between the welding surfaces shall not be greater than half of the maximum tolerance of the corresponding size (see Figure 7) ±4D
When A>AdAD/2
The unindicated tolerance value of the verticality and parallelism between the surfaces of the welded parts shall not be greater than half of the maximum tolerance of the corresponding size (see Figure 8). 3.6.7
The unindicated tolerance value of the symmetry between the surfaces of the welded parts shall not be greater than half of the tolerance of the corresponding reference surface size (see Figure 9). L±AL
3.6.9 Correction of welding deformation: Correction in hot state is generally not allowed at the blue brittle temperature (250~500℃) (except for quenched and tempered steel); correction in cold state is not allowed at the cold brittle temperature (-20℃). When using flame correction, it is strictly forbidden to heat the same part repeatedly to prevent changes in the metallographic structure and mechanical properties of the steel. For important parts, it is strictly forbidden to use rapid cooling methods such as water cooling and air cooling, and it is also not allowed to repeatedly correct tensile and compressive stresses in the same part. After correction, the surface of the welded parts shall not have cracks, pits or other defects that affect the strength and appearance of the welded parts. 3.6.10 Surface quality grading of welds and their shape deviations and external defects 3.6.10.1 Surface quality grading of welds shall be in accordance with the provisions of Table 16. 3. 6. 10.2
Weld shape deviations and external defects shall comply with the provisions of Table 17. Table 16
Ordinary welds
1. Important welds required by the structural drawings
Applicable scope
2. Important welds of major components (for example: boom, dipper arm, bucket, platform, balance beam, frame, arch frame, fan blades, etc.) 3. Welds that need to be repaired
4. Welds used as strength structural parts or when high-strength steel plates are used 5.Welds of hydraulic parts (e.g. hydraulic cylinders, oil tanks, etc.) Other structural parts
Not fully welded and
pits.
Misalignment m
Weld width
Uneven along the length
Weld leg size
Incorrect Ae
Uneven welding wave
Weld discontinuity
Double-sided weld
Single-sided weld
JB/T5943—1991
Key weld
h≤1+0.10c
h≤1+0.10k
but not greater than 4
9≤0.2±0.028
but not greater than 0.5
butt weld
fillet weld
ordinary weld
h≤1+0.15C
h≤1+0.14k
but not greater than In 5
q≤0.2±0.04h
but not more than 1.0
The cumulative length does not exceed 10% of the total length of the weld
m≤0.158
but not more than 3
m≤0.106
but not more than 2
More than 90% of the welds must meet
the following provisions
C>20~30
The cumulative length does not exceed 20% of the total length of the weld
m≤0.208
but not more than 5
but not more than 3
More than 80% of the seams must meet
the following provisions
Within the residual height deviation range
Not allowed
Not allowed
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