JB/T 5000.7-1998 General technical conditions for heavy machinery repair welding of steel castings
Some standard content:
ICS 77. 140.80
J31
JB
Machinery Industry Standard of the People's Republic of China
JB/T5000.7-1998
General technical conditions for heavy machinery| |tt||Repair welding of steel castings
The heavy mechanical general techniques and standardsRepairweldingforsteel castings1998-09-30 Released
National Machinery Industry Bureau
Released
1998-12 -01 Implementation
JB/T5000.7-1998
Appendix A of this standard is an appendix to the standard.
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Words
This standard was proposed and managed by the Deyang Large Forging Research Institute of the Ministry of Machinery Industry. This standard was drafted by: Shenyang Heavy Machinery Group Co., Ltd. The main drafter of this standard: Xu Zongjian.
1Scope
Mechanical Industry Standards of the People's Republic of China
General Technical Conditions for Heavy Machinery
Repair Welding of Steel Castings
The heavy mechanical general techniques and standardsRepair welding for steel castingsJB/T 5000.7—1998
This standard specifies the technical requirements for pre-weld preparation, technical requirements for repair welding, post-weld heat treatment and inspection for repair welding of steel castings. This standard applies to manual arc welding repair welding of defects in carbon steel, low alloy steel and high manganese steel castings before finishing. 2 Referenced standards
The provisions contained in the following standards constitute provisions of this standard through reference in this standard. At the time of publication, the editions indicated were valid. All standards are subject to revision and parties using this standard should explore the possibility of using the latest version of the standard listed below. GB98485
GB/T5117-1995
GB/T5118-1995
JB3223-96
surfacing electrodes
carbon steel electrodes
Low alloy steel welding rods
Quality Management Regulations for Welding Materials
Steel Parts
JB/T5000.6--1998 General Technical Conditions for Heavy Machinery JB/T 6404 - 92
3 Technical requirements for preparation before welding
Large high manganese steel and other parts
3.1 Defect cleaning and groove type
3.1.1 Defects must be completely removed before repair welding, and the groove surface should be The repair should be smooth and smooth, with no sharp corners. 3.1.2 Depending on the defects of the steel castings, defects in the repair welding area can be removed by shoveling, grinding, carbon arc gouging, gas cutting or machine processing. For steel castings with poor weldability, when carbon arc gouging and/or gas cleaning are used to clean defects, they should be preheated according to Table 2 before cleaning the defects. After carbon arc gouging, the carburized layer must be removed by grinding, ||tt ||3.1.3 Sand, oil, water, rust and other dirt within 20mm around the repair welding area and groove must be completely removed. 3.1.4 The groove type for repair welding of casting defects can be selected according to Table 1. The State Machinery Industry Bureau approved the implementation on 1998-09-30 and 1998-12-01
1
missing
Unpenetrating cracks
Effect or holes
Penetrating cracks
Penetrating cracks
Or between holes and grooves
Too big
Larger size
Penetrating defects
Seam name
U-shaped or
Square, round
Pure edge V
shaped or blunt edge
|tt||With mirror block
V
shaped or blunt edge
Bevel type
quilt
type
style
bevel size
g-10°15°
R=6~8 mm
4=60*±5*
P=2~4mm
<70 mm
a*10*~15*
P- 2~4mm
R=6~8mm
270mm
e55*±5*
P=2~4 mm
The pads are made of the same material
Or low carbon steel plate
a60*±5*
p=2~4mm
Inserts are made of the same material
Convenient pieces||tt ||For crack defects, in order to prevent crack expansion, you can drill anti-crack holes with a diameter of not less than 10mm at both ends of the crack, and then open the slope 3. 1. 5
,
3.1.6 Before repair welding, magnetic particle flaw detection or liquid penetration method and other methods should be used to inspect the repair welding parts of steel castings in accordance with relevant regulations to confirm that the defects have been completely removed.
3.2 Preheating before welding
3.2.1 The preheating leakage degree of preheating before welding shall be in accordance with Table 2. The preheating temperature of steel types other than Table 2 shall be in accordance with Appendix A (Standard Appendix ) in 2
A2 is executed.
Category
Cast
Paper
Low
Taiwan
Gold
Steel
High|| tt||Cast steel grade
ZG200-400
ZG230-450
ZG270-500
ZG310-570
ZG340-640||tt| |ZG30Mn
ZG40Mn
ZG40Mn2
2G50Mn2
ZG20Mn
ZG35Mn
ZG35SiMnMo
ZG35CrMnSi
ZG20MnMo
ZG55CrMnMo
ZG40Cr1
ZG34Cr2Ni2Mo
ZG17CrMo
ZG15Cr1Mo1V
ZG20CrMo
ZG35Cr1Ma
ZG42Cx1Mo|| tt||ZG50Cr1Mo
ZG28NiCrMo
ZG30NiCrMo
ZG35NiCrMa
ZGMn13-1
ZGMn13-2
ZGMn13-3||tt| |ZGMn13-4
Preheating temperature
c
100~150
200~350
200~250
250~300
350~450
150~200
200~250
250~350
150~200
350~450|| tt||250~350
350~450
250~300
300350
JB/T5000.7—1998
Table 2||tt ||Preheating temperature for repair welding of steel castings
Preparation
No preheating
Note
Generally no preheating. When the shape is complex, the defects are large, and the stiffness is large, it is necessary to preheat the crack propensity, and strictly control the temperature
The crack tilt is large, and the temperature is strictly controlled
Strictly control the degree of crack
The crack propensity is large , Strictly control the temperature
Strictly dig the rigor
Poor coal welding performance, Bureau Veritas strictly controls the spectrum, large crack tendency, strictly control the temperature
Poor welding performance, strictly control the speed
Cracks will grow larger, strictly control the temperature
No pre-heating, repair welding after water toughening treatment
Note: +2G17CrMo is equivalent to DINGS17CrMo55.3. 2. 2||tt || Preheating can use overall preheating or local preheating. When local preheating is used, no matter how big the defect is, the width of the preheating range on each side of the defect should not be less than the wall thickness of the cast copper part at the repair welding site. 2 times, and shall not be less than 75mm. 3
JB/T 5000.7-1998
3.2.3. During the entire process of repair welding, the temperature in the preheating zone of the steel casting shall not be lower than the lower limit of the preheating temperature specified in Table 2. 3.3 Selection and use of welding rods
3.3.1 The chemical composition and mechanical properties of steel castings that require repair welding should comply with the regulations of JB/T5000.6 and JB/T6404. According to the material of the steel casting that needs to be repaired and the strength of the weld, select the welding rod according to the provisions of Table 3. Table 3 Welding rods for repair welding of steel castings
Class
Speciality
Huan
Cast
Steel
Low
He
Strive
Sell
Potential vehicle brand
ZG200-400
ZG230-450
2G270-500
ZG310-570
ZG340-640
ZG30Mn
ZG40Mn
ZG40Mn2
ZG40Mn2
ZG50Mn2
ZG20Mn||tt ||ZG35Mn
ZG35SiMnMo
ZG35SiMnMo
ZG35CrMnS
ZG20MnMo
ZG5SC:MnMo
ZG40Cr1
ZG34Cr2Ni2Mo||tt ||ZG20CrMo
ZG17CrMa
ZG15Cr1Mo1V
ZG35Cr1Mo
ZG42Cr1Mo
ZG50CriMo
ZG28NiCrMo
ZG30NiCrMo
ZG35NiCrMc
No need to wait
Strong
Degree
Welding rod model (national standard)
E4303
E4303.E4315||tt| |E5016,E5015
E5016.E5015
E6016-D1.E6015-D1
E4303.E4315
E5016.E5015
E6016-D1.E6015 -D1
E5016.E5015
E4316,E4315
EDRCrMnMo-15
E5016.E5015
E7015-D2.E7515-G||tt| |E5515-B2
E5016.E6016-D1
E5016.E5015
E5016.E6016-D1
Welding rod brand
J422
J422.J427
J506.J507
J506.J507
J6063607
J422.J427
J506.J507
J606.J607| |tt||J506.J507
J426.J427
D397
J506.J507
J707.J757
R307
J506. J606
J506.J507
J506.J6D6
requires equal strength
degree
electrode model (national standard)
E5016.E5015
E5516-G,E5515-G
E6016-D1,E6015-D1
E5516-G,E5515-G
E6016 -D1,E6015-D1
E7515-G
E5016.E5015
E6016-D1.E6015-DI
E7015-D2
E5016,E5015
EDRCrMnMo-15
E6016-D1,E6015-D1
E8515-G
E5515-B2
E7015-D2
E6016 -D1.E6015-D1
E7015-D2
D7515-G
Welding rod grade
J422,J427
J506,J507
J556,J557www.bzxz.net
J606.J607
5556.J557
J606,J607
J757
J506.J507
J606.J607| |tt||J707
J506.J507
D397
J606.J607
J857.J857Cr
R307
J707||tt ||J606.J607
J707
J757.J757N;
Class
Speciality
Cast steel grade
ZGMn13-1|| tt||ZGMn13-2
ZGMn13-3
ZGMn13-4
JB/T 5000.7—1998
Table 3 (End)
Not required Equal strength
Welding rod model (national standard)
EDMn-A-16EDMn-B-16
Bad rod grade
D256.D266
Requirements, etc. Strong
Degree
Welding rod model (national standard)
EDMn-A-16.EDMn-B-16
Welding rod brand
D256,D266| |tt||Note: Since the strength of some steel types varies greatly under different heat treatment states (quenching and tempering or normalizing + tempering), the bar models selected are also different. The strokes in this table are marked with ", \ No. of cast steel grades, the treatment state changes into quenching and tempering state. 3.3.2 Welding rods used for repair welding of defective steel castings should comply with the regulations of GB984, GB/T5117.GB/T5118 and JB3223. 3.3.3 The welding rod must be dried before use. If there are no special provisions in the welding rod instructions, the acidic welding rod should be dried at 75~150C for 1~2h depending on the traceability. The alkaline low nitrogen structural steel welding rod should be dried at 350~400C for 1~2h. The dried welding rod should be placed in 100~150C insulation brief (box) ready to use, pay attention to keep dry when using. 3.3.4 Low-hydrogen welding rods should be re-dried if left at room temperature for more than 4 hours. The number of repeated baking times should not exceed 3 times. 3.4 It is not suitable to carry out repair welding in places with air convection, and the room temperature should not be lower than 10C. 4 Technical requirements for repair welding
4.1 Welders responsible for repair welding must obtain qualification certification from the designated department before they can operate. 4.2 When one of the following situations occurs, the welder should be re-assessed; a) When the welder has not operated in accordance with this standard for 3 months or more: b) When there is reason for the welder to weld a weld that meets this standard When ability is in question. 4.3 Repair welding of defects in steel castings should be carried out after the casting stress has been eliminated. 4.4 The scope of allowable repair welding of defects should be implemented in accordance with relevant regulations such as drawings or ordering technical conditions. 4.5 When conditions permit, welding should be carried out in a horizontal position as much as possible. 4.6 Repair welding work should be carried out continuously when conditions permit. If interruption is necessary, insulation measures must be taken. When repair welding is carried out again, the provisions of 3.2.1 shall be complied with.
4.7 During repair welding, the welding rod should not swing too much laterally, and the swing amplitude should not exceed 3 times the diameter of the welding rod. Welding keys with long lengths should be segmented and staggered welding to reduce the generation of deformation stress, ||tt ||4.8 During the repair welding process, if cracks, lack of fusion, pinching, pores and other defects that affect quality are found, the quality inspector should be reported and measures should be taken to remove the defects. Repair welding can only be continued after confirming that the defects have been removed. 4.9 When surface surfacing of steel castings is welded, the amount of overlap between weld passes shall not be less than 1/3 of the weld bead width. 4.10 When repair welding of rigid steel transfer parts or multi-layer welding, except for the first and last layers In addition, each weld pass of the other layers should be properly paved with a flat round-head air shovel,
5 Post-weld heat treatment
5.1 When the groove depth of the repair welding part of the steel casting exceeds 20% or 25mm of the wall thickness of the location (whichever is smaller), stress relief heat treatment should be carried out after repair welding
5.2 If necessary, an intermediate stress-relieving heat treatment can be performed at 1/3 to 1/2 of the groove depth during repair welding. After the stress-relieving heat treatment, continue to weld to fill the groove. Finally, perform a stress-relieving heat treatment. 5.3 Depending on factors such as the material, structure and defects of the steel castings, if necessary, put them into the furnace immediately after welding for stress relief heat treatment. 5.4 The automatic recording curve should be kept during the stress relief heat treatment after the whole machine is put into the furnace. 5
Inspection
6
JB/T5000.7—1998
6.1 The inspection personnel shall clean and groove the defects in the repair welding area in accordance with the provisions of this standard. Check the production status, welder qualifications and the drying status of the welding rod. Repair welding can only be carried out after passing the inspection. 6.2 After repair welding, the welded parts should comply with the drawings and technical requirements, and be inspected according to the same standards as steel castings. 6.3 For repair welding of major defects in steel castings and export products, there must be repair welding technical records. The repair welding technical record should record the actual situation during the repair welding process in a timely, correct and true manner,
JB/T5000.7—1998
Appendix A
(standard appendix)| |tt||Supplementary provisions for preheating temperature
The commonly used carbon equivalent calculation formula for carbon steel and low alloy steel (recommended by the International Welding Society IW) is shown in formula (A1): Al
Ce(%)= C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15 Carbon steel and low alloy steel preheating temperature calculation formula (empirical formula) is shown in formula (A2): A2
T=CgX360
Where: T-
preheating temperature, C:
C--carbon equivalent, %.
(A1)
(A2)
Steel castings with a carbon equivalent of less than 0.4% are generally not heat welded. However, when one of the following conditions exists, it should be preheated to 100150C before Proceed to A3
for repair welding:
a) When the steel casting for repair welding is an important part:
b) When the steel casting for repair welding is very rigid: ||tt ||c) When the temperature of the workshop operating environment is not higher than 10C, the A4 preheating temperature should be measured at a distance of 75 to 100mm from the heat affected zone outside the fusion line of the repair welding area.
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