JB/T 5000.3-2007 PDF in English
JB/T 5000.3-2007 (JB/T5000.3-2007, JBT 5000.3-2007, JBT5000.3-2007)
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| JB/T 5000.3-2007 | English | 85 |
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Heavy mechanical general techniques - Part 3: And standards welding
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| JB/T 5000.3-1998 | English | 559 |
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The heavy mechanical general techniques and standards. Welding
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JB/T 5000.3-2007: PDF in English (JBT 5000.3-2007) JB/T 5000.3-2007
JB
NATIONAL MACHINERY INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 25.160
J 33
Record number. 21697-2007
Replacing JB/T 5000.3-1998
Heavy mechanical general techniques
- Part 3. And standards welding
ISSUED ON. AUGUST 28, 2007
IMPLEMENTED ON. FEBRUARY 1, 2008
Issued by. National Development and Reform Commission, People’s
Republic of China
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 General requirements ... 6
4 Preliminary straightening of steel ... 7
5 Forming bending of steel ... 8
6 Welding assembly ... 11
7 Welding ... 12
8 Machining allowance of welded structural parts ... 18
9 Welded joints and grooves ... 19
10 Inspection ... 19
11 Drawing indications ... 20
Foreword
JB/T 5000 “Heavy mechanical general techniques and standards” is divided
into 15 parts.
- Part 1. Check of product;
- Part 2. Oxygen cutting workpiece;
- Part 3. And standards welding [Translator note. should be “Welding”];
- Part 4. Iron Casting;
- Part 5. Non-ferrous casting;
- Part 6. Steel Castings;
- Part 7. Repair welding for steel castings;
- Part 8. Forging;
- Part 9. Cutting;
- Part 10. Assembly;
- Part 11. Attached piping;
- Part 12. Paint;
- Part 13. Packing;
- Part 14. Non-destructive inspection of cast steel;
- Part 15. Non-destructive inspection of forged steel.
This Part is Part 3 of JB/T 5000.
This Part replaces JB/T 5000.3-1998 “The heavy mechanical general
techniques and standards - Welding”.
As compared with JB/T 5000.3-1998, the main changes of this Part are as
follows.
- ADD the requirement for chamfering the edges and corners of the bent steel
part when the steel is rolled.
- ADD length, weld angle, and quality requirements for tack weld.
Heavy mechanical general techniques
- Part 3. And standards welding
1 Scope
This Part of JB/T 5000 specifies the technical requirements, inspection methods,
and drawing indications of steel welded parts.
This Part applies to steel welded parts by shielded metal arc welding, gas
shielded welding, and submerged arc welding in heavy machinery and
components.
Where there are no special requirements in product drawings, technical
documents, and ordering technical conditions, the provisions of this Part shall
be complied with.
2 Normative references
The clauses in the following documents, by reference in this Part of JB/T 5000,
constitute the clauses of this Part. For the dated references, the subsequent
amendments (not including errata content) or revisions do not apply to this Part.
However, parties which have reached an agreement according to this Part are
encouraged to study whether the latest edition of these documents can be used.
For the undated references, the latest edition is applicable to this Part.
GB/T 324 Welds - symbolic representation on drawings (GB/T 324-1988, eqv
ISO 2553.1989)
GB/T 985 Basic forms and sizes of weld grooves for gas welding, manual
arc welding and gas-shielded welding
GB/T 986 Basic forms and sizes of weld grooves for submerged arc welding
GB/T 2649 Methods of sampling for mechanical properties tests of welded
joint
GB/T 2650 Impact test methods on welded joints
GB/T 2651 Tensile test method on welded joints
GB/T 2652 Tensile test methods on weld and deposited metal
GB/T 2653 Methods of bend and compression tests for welded joint
GB/T 2654 Methods of hardness tests for welded joint and surfacing metal
GB/T 3323 Radiographic examination of fusion welded joints in metallic
materials (GB/T 3323-2005, EN 135.1997, MOD)
GB/T 11345 Non-destructive testing of welds - Ultrasonic testing -
Techniques, testing levels, and assessment
JB/T 3223 Welding material quality management procedures
JB/T 4735 Steel welded atmospheric pressure vessels
JB/T 5000.2 Heavy mechanical general techniques and standards - Part 2.
Oxygen cutting workpiece
JB/T 5000.11 Heavy mechanical general techniques and standards - Part 11.
Attached piping
JB/T 5000.12 Heavy mechanical general techniques and standards - Part 12.
Paint
JB/T 5926 Vibrating stress relief effect - Evaluation methods
JB/T 6046 Welding assembly for carbon steel and low alloy steel - Post-
welding heat treatment method
JB/T 6061 Non-destructive testing - Magnetic particle testing of welds
JB/T 7949 Weld outer dimensions for steel construction
3 General requirements
3.1 Welded parts shall be manufactured in accordance with the design drawings,
process documents, and this Part.
3.2 The steel grade, specifications, and dimensions of the raw materials (steel
sheets, section steel, and steel pipes, etc.) used to manufacture the welded
parts shall comply with the requirements of design drawings. For material
substitution, substitution sheet shall be handled in accordance with relevant
regulations.
3.3 Raw materials and welding materials (welding rods, welding wire, flux,
shield gas, etc.) used to manufacture welded parts shall, when entering the
factory, based on the certificate of compliance provided by the supplier,
5 Forming bending of steel
5.1 For the rolling bending of steel, when the bending radius (inner radius) is
greater than the following values, cold bending can be carried out (SEE Figure
1). However, regardless of cold bending or hot bending, the edges and corners
of the steel sheet near the bent part shall be chamfered.
5.1.1 Steel sheet. For low alloy steel, R≥25δ;
For low carbon steel, R≥20δ.
R - Bending radius; δ - Thickness of steel sheet.
5.1.2 I-beam. R≥25H or R≥25B (depending on the direction of bending);
H - I-beam’s height; B - I-beam’s width.
5.1.3 Channel steel. R≥45B or R≥25H (depending on the direction of bending);
H - Channel steel’s height; B - Channel steel’s width.
5.1.4 Angle steel. R≥45B;
B - Angle steel’s edge-width (for unequal angle steel,
depending on the direction of bending).
5.2 For the rolling bending of steel, when the bending radius (inner radius) is
less than the values specified in 5.1, according to the specific situation, the
technician shall determine whether to perform annealing heat treatment after
hot bending or cold bending.
5.3 The tolerances for the dimensions of bend formed cylinder shall be in
accordance with Figure 2 and Table 3.
5.4 The unfitness of butt joint e for the butt joint between cylinders or for the
longitudinal joint of cylinder shall not exceed 20% of thickness and no more
than 4mm (SEE Figure 3 and Figure 4).
5.5 For the bend forming of the pipe, during hot bending, the heating
temperature is 900°C~1000°C. During bending, the temperature shall not be
lower than 700°C. Cold bending shall be carried out on a special pipe bender.
5.6 The bending radius R of the pipe (SEE Figure 5) shall comply with the
provisions of JB/T 5000.11.
7.1.1 Welders shall be specially trained and qualified before they can perform
welding work.
7.1.2 If the steel is not pretreated, before welding, the surface dirt of welding
area shall be removed, such as rust scale, oil stain, paint, and other impurities
which affect the quality of weld. The cleaning area is not less than 20mm from
the edge of the weld.
7.1.3 During open-air welding, in case of rain, snow, heavy fog, and strong wind,
if no protective measures are taken, welding shall not be carried out.
7.2 Preheating before welding.
7.2.1 Welded parts of low carbon steel can generally be welded without
preheating. But when the ambient temperature is lower than 0°C, or the
thickness is large, before welding, according to the process requirements,
preheating and slow cooling must be carried out.
7.2.2 For welded parts of low alloy structural steels, factors such as carbon
equivalent, component thickness, restraint degree of welded joint, ambient
temperature, and the welding material used must be considered, to determine
the welding preheating temperature. Table 5 gives the recommended
preheating temperature. When using non-low hydrogen welding materials to
weld, the critical thickness shall be appropriately reduced; or the preheating
temperature shall be appropriately increased. The preheating temperature of
the specific components is determined by the welding technician according to
the specific conditions.
7.2.3 The preheating temperature of welding between different materials is
selected according to one with poor weldability.
7.2.4 When the material is the same and the thickness is different, the welding
preheating temperature is selected according to one with larger thickness.
7.2.5 The preheating area is not less than 2δ (δ is the thickness of the sheet)
from the center of weld on each side of the weld; and is not less than 75mm.
7.2.6 The welding preheating temperature, interlayer temperature, post-heating
or post-welding heat treatment for special materials or special structures shall
be carried out according to the process requirements.
Table 5
Steel grade Thickness mm
Preheating before
welding °C Steel grade
Thickness
mm
Preheating before
welding °C
Q295 - No preheating Q390 >32 ≥100
Q345 >40 ≥100 Q420 - ≥100
requirement, important welded parts
B F Less important structure, small thermal deformation caused by welding and straightening, batch production
C G General structure, such as box structure; large thermal deformation caused by welding and straightening
7.4 Weld quality requirements and defect classification of welded joint are
shown in Table 10. The weld outer dimensions for steel construction shall be in
accordance with JB/T 7949. Weld quality evaluation levels are performed
according to the provisions of Table 11 and are marked on the drawings.
Table 10
Defect name
GB/T
6417.1
code
Defect classification
I II III IV
Incompletely filled
weld (insufficiency)
design requirements
511 Not allowed
≤0.2+0.02δ and ≤1mm
Total defect length
≤25mm per 100mm
weld
≤0.2+0.04δ and
≤2mm
Total defect length
≤25mm per
100mm weld
Root contraction 515 5013
Not
allowed
≤0.2+0.0
2δ and
≤0.5mm
≤0.2+0.02δ and ≤1mm ≤0.2+0.04δ and ≤2mm
Unlimited length
Undercut 5011 5012 Not allowed
≤0.05δ and ≤0.5mm;
continuous length
≤100mm; and the total
length of undercut on
both sides of the weld
is ≤10% of the total
length of the weld
≤0.1δ and ≤1mm;
unlimited length
Crack 100 Not allowed
Crater crack 104 Not allowed
Individual crater
cracks of length
≤5mm are allowed
Arc scratch 601 Not allowed
Individual arc
scratches are
allowed
Splash 602 Clean up
Poor joint 517 Not allowed
Cause the depth of
gap ≤0.05δ and
≤0.5mm;
no more than one per
meter weld
The depth of gap
≤0.1δ≤1mm; no
more than one per
meter weld
requirements of Table 13.
Table 13 Unit. mm
9 Welded joints and grooves
The forms and sizes of welded joints and grooves shall comply with the
provisions of GB/T 985 and GB/T 986. Under the premise of ensuring the
effective thickness of weld and the welding quality, the manufacturer can,
according to the welding method, adopt the groove form different from the
drawing.
10 Inspection
10.1 The type dimensions of weld and the shape and dimensions of welded
parts shall be in accordance with the requirements of the drawings, process
documents, and this Standard.
10.2 The manufacturer shall provide inspection reports and certificates of
compliance for welded parts.
10.3 The full water test, hydraulic test, air tightness test, and kerosene leakage
test can be carried out in accordance with the relevant provisions of JB/T 4735.
10.4 Ultrasonic testing of welds shall comply with the provisions of GB/T 11345.
10.5 Radiographic testing of welds shall comply with the provisions of GB/T
3323.
10.6 The magnetic particle testing of weld surface shall comply with the
provisions of JB/T 6061.
10.7 When the weld needs to be reworked, according to the rework process
document, it shall be carried out.
10.8 Welds which require mechanical properties testing shall be noted in the
drawings or ordering technical requirements. The type of mechanical properties
tests and the sample size for welds shall be in accordance with the provisions
Nominal dimension Nominal dimensionAllowance Allowance
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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