Work instructions for welding of stainless steel |
1 Overview
Installed capacity: 2 * 150T/h+2 * 30MW, the turbine generator sealing oil pipeline, the material is 1Cr18Ni9Ti.
Name of project: stainless steel pipe welding operation instruction
2 compilation basis:
2.1. design drawings
2.2. thermal power plants "welding" technical specification for DL/T 869-2004
2.3. "fire construction quality inspection and assessment standards (welding articles)" 1996 edition
2.4. "the welder technical assessment procedures"
2.5. "electric power construction safety work rules"
3 construction preparation:
3.1. material and equipment
3.1.1. welding materials
Wire: H1Cr18Ni9Ti 2.5
Certificate of quality shall be wire factory, the collection and payment of the unified management of welding material manager. The wire should remove oil and rust and other dirt before use, with metallic luster.
3.1.2. ar
Argon gas cylinders should be affixed with the factory quality label, with the purity of more than 99.95%, the flow 6-9 liters / min, cylinders in argon gas can not be exhausted, bottle of excess pressure shall not be less than 0.5MPa, to ensure that the argon purity.
3.2. construction equipment
3.2.1. uses a DC electric welder.
3.2.2. use the JL-15 type argon decompression flowmeter. The meter should be freely opened and closed without leakage. Remember not to open the flow meter, after the open cylinders, caused by high pressure airflow into the low pressure, damage flowmeter; shut off the first flow meter and then close the argon gas cylinder.
3.2.2 transport argon rubber tube, not with other gas rubber conveying pipe is mutually on, alternative available new oxygen rubber tube, the length of not more than 30 meters.
3.2.4. other instruments
The welder should have: hammer, sandpaper, flat shovel, steel wire brush, electric grinding tools, for slag and elimination.
4 process
4.1. welder must be in accordance with the "test rules" provisions of the corresponding test piece after passing the examination, be on the position of welding.
4.2. is prohibited in the surface of welding arc ignition, random test current welding or temporary support etc..
4.3 welder with argon arc welding, argon decompression flowmeter, should always check, ensure the bottom of argon arc welding argon as laminar flow.
4.4. Counterparts before should be the inner wall and the outer wall of the groove surface and the base material of oil, paint, rust, etc. clean until it makes a metallic luster, cleaning up the range of each side of each for the 10-15mm. Corresponding clearance for 2.5 ~ 3.5mm.
4.5. pipe counterpart center line deviation value does not exceed 1/100, gap to straight, no strong counterpart, the wrong port wall thickness value should be less than 10%, and no more than 1mm.
4.6. local weld gap is too large, should be repaired, do not add the obstructions in the gap.
4.7. to qualified, should be based on different diameter 2-3, welding material should be the same as the formal welding, spot welding length of 10-15mm, thickness of 3-4mm.
4.8. pipe welding, Chuantangfeng pipe pipe shall not, and shall be shaking, precautions.
4.9. rendering is completed, you should carefully check the backing weld quality, qualified after cover welding argon arc welding.
4.10. arc, arc must be carried out in the groove to fill arc weld pool, will lead to the extinction of arc groove.
4.11. spot, argon arc welding, cover welding surface, such as the generation of defects must be uses an electric grinder tool grinding in, and then continue to weld, shall not be used repeated melting method to eliminate the defects.
4.12. should pay attention to and end joint quality, pay attention to the fusion joint should be good, when filled with molten pool arc. In order to ensure the tightness of the weld, all welded seam is at least two welding layer, not once complete, the interlayer joints should be staggered over 10mm, to alleviate the backing weld oxidation degree should be adapted to lower layer temperature.
4.13. cover surface of the end should promptly clean up the weld surface slag and spatter, after inspection, in the vicinity of the weld their code stamp.
. weld the non-destructive testing, such as excessive defects, available patching repair, but the same position on the number of times the scarf shall not more than three times, and do it:
A. completely clear defects.
B. Welding, according to the original process requirements.
5 control points:
5.1. counterparts can assembly inspection, spot welding or welding, a witness point.
5.2. welding is completed by a self qualified welder I stamp code, is a witness point.
6 quality standard:
6.1. internal quality evaluation according to the DL/T5069-96 standard, grade I qualification.
6.2. weld surface quality according to the "standard for quality inspection and evaluation of thermal power construction (welding section)" (1996 edition) Regulations for inspection, welding joint surface quality standard (excellent):
Weld weld over smooth, straight, good joint
The enhanced surface height: 0-3mm
Weld width: less than 3mm
The wrong port wall is less than or equal to 0.1 and less than 4 Delta.
Bend: less than 1/200
Undercut: H = 0.5, I = 40 and sigma = 0.1L
Crack, arc pit, porosity, slag: no
6.3. check
6.3.1. inspection
After 100% welder welding complete self-test, self inspection record, shift (Group) to send a long re construction team.
6.3.2. re construction team
Welding Inspectors according to the class (Group) submitted by the welders self table, according to the "welding" standard and proportion inspected, preliminary assessment of welded joint surface quality grades, the results will fill in "sub project welding joint surface quality inspection and evaluation form".
6.3.3. by the technician to "welding" provisions of the proportion of Commission for nondestructive testing.
The construction team is 6.3.4.
According to the welding of the provisions of article "standard, welding joint surface quality grades, tightness test evaluation and test department to provide the test report rating, fill in the sub project welding comprehensive quality rating table, and a preliminary assessment of the welding quality grade, sent to the company's quality inspection departments assessment.