Hainan Steel Works Welding procedure qualification

1, the construction unit for the first time using steel, welding materials, welding, joint type, welding position, post weld heat treatment and other combinations of various parameters and parameters should be before the steel structure fabrication and installation of welding procedure qualification test. Welding procedure qualification test methods and requirements, as well as exemption procedure qualification limits should be consistent with existing national standards "Steel Welding Code" of the relevant provisions of GB50661.
2, before the welding work, Hainan steel construction units should be qualified welding procedure qualification results or use exemption process in line with the condition assessment based on the preparation of welding procedure documents and shall include the following:
(1) a combination of welding or soldering method.
(2) base material specifications, grade, thickness and coverage.
(3) filler metal specifications, categories and models.
(4) in the form of welded joints, groove forms, dimensions and tolerances.
(5) welding position.
Type and polarity (6) welding power source.
(7) gouging process.
(8) welding parameters (welding current, welding voltage, welding speed, weld bead layer and distribution).
(9) Road between preheating temperature and temperature range.
(10) post-weld stress relief treatment process.
(11) other necessary requirements.
3, when the welding operation area ambient temperature, relative humidity and wind speed should meet the following requirements when the provisions of this section and must be beyond the weld, shall prepare special programs:
(1) operating ambient temperature should not fall below -10 ℃.
(2) Relative humidity welding work area shall not be greater than 90%.
(3) When the SMAW and self-shielded flux-cored arc welding, welding work area shall not exceed the maximum wind speed 8m / s, when the gas shielded arc welding work area shall not exceed the maximum wind speed 2m / s.
4, high-altitude site erection welding work should be a solid operating platform and protective shed.
5, before welding should be used wire brushes, grinding wheels and other tools to remove oxide surfaces to be welded at the rust, oil and other debris, weld groove should be checked according to the current national standard "steel welding specifications" of the relevant provisions of GB50661 .
6, welding parameters welding procedure qualification of the job should be.
7, when the welding operation at ambient temperatures below 0 ℃ and not less than -10 ℃, heating or protective measures should be taken, should be welded joints and weld surface in each direction is greater than or equal to 2 times the plate thickness not less than 100mm range the base material is heated to a predetermined minimum temperature is not lower than 20 ℃ preheating before welding.
Ⅲ tack welding
8, positioning the weld thickness not less than 3mm, design throat thickness should not exceed 2/3. Length less than 40mm and joints four times the thickness of the thin part. Spacing is preferably 300mm ~ 600mm.
9, positioning the weld seam with the official should have the same welding process and weld quality requirements. Multi-channel positioning weld ends should be stepped. Using steel liner plate of welded joints, tack welds should be carried out within the joint groove. Preheat temperature should be higher than the official positioning welding welding preheat temperature of 20 ℃ ~ 50 ℃.
Ⅳ arc plate, lead plate and spacer plate
10, when the arc plate, lead plate and spacer plate when the steel should be used in yield strength is not greater than the nominal strength steel is welded steel, and weldability should be similar.
11. The end portion of the welded joint should be set arc weld plate, lead plate. Arc welding and gas shielded arc welding lead length should be greater than 25mm, submerged arc welding seam extraction length should be greater than 80mm. Welding is completed and fully cooled, can be flame cutting, carbon arc gouging or mechanical methods to remove the arc plate, lead plate, and grinding should be smooth, non-shoot down with a hammer.
12, steel liner plate should be snug fitting connection with the base material, the gap should not be greater than 1.5mm, and should be fully weld fusion. When the SMAW and gas shielded arc welding, steel liner plate thickness not less than 4mm. When submerged arc welding, steel liner plate thickness not less than 6mm. When electroslag welding steel liner plate thickness not less than 25mm.
Ⅴ preheat and interpass temperature control
13, between the channel and preheat temperature control should be adopted electric heating, flame heating and infrared heating and other heating methods, and should be dedicated thermometer measurements. Preheating heating area should be on both sides of the welding groove, the width should be at the welding weldment thickness of more than 1.5 times, and not less than 100mm. Temperature measurement point, when a non-member enclosed space, preferably on the back surface of the weldment heat from both sides of the weld groove at not less than 75mm. When the member is a closed space, preferably in the front side from the weld groove at not less than 100mm.
14, preheat temperature of welded joints and track temperatures should be consistent with existing national standards "Steel Welding Code" of the relevant provisions of GB50661. When the process selected preheating temperature lower than the current national standard "Steel Welding Code" GB50661 the relevant provisions should be determined by the procedure qualification test.
15, welding technology and welding sequence used should be deformed and contraction member minimum, the following sequence can be used to control the welding deformation:
(1) butt joints, T-joints and cross joints, in the case of component or place conditions permit easy flip, it should be double-sided symmetrical welding. Symmetrical cross-section of members, should be symmetrical with respect to the neutral axis welding member. Symmetrical connection node of the rod, the node should be symmetrical axis of symmetry while welding.
(2) double-sided asymmetric groove weld advised to weld deep groove side portion of the weld, then weld fully shallow groove side to finalize the deep groove side of the weld. Special plate should increase turns symmetrical welding cycles.
(3) long welds should adopt the back-step welding method, stitch welding method or more symmetrical welding.
16, when the member welding, welding should be used to reserve the shrinking margin or pre-reverse deformation method of controlling shrinkage and deformation, shrinking margin and anti-deformation value should be determined by calculation or test.
17, when the member assembly welding, welding should be a greater amount of shrinkage joints, small amount of shrinkage after welding joints, welding joints shall be binding in smaller states.
18, design documents or the contract documents after welding to eliminate stress when required and be subjected to tensile stress butt or weld-intensive components by fatigue check nodes or structure, should adopt the electric heater and partial annealing furnace annealing overall and other methods of stress relief treatment. When only stable structure size, vibration method can be used to eliminate stress.
19, the heat treatment should comply with industry standard "carbon steel, low alloy steel member after welding heat treatment method," the relevant provisions of JB / T6046 after welding. When using an electric heater for welding components for local stress relief heat treatment shall meet the following requirements:
(1) equipped with automatic temperature controller heating equipment, heating, temperature, temperature control performance should meet the requirements.
(2) each side of the heating plate weld member (band) width should be at least 3 times the plate thickness, and not less than 200mm.
Both sides of the outside member (3) heating plate (with) suitably covered with insulating material.
20, with a hammer welding method to eliminate the intermediate layer of stress, you should use a hammer or a small round vibrating hand tools, should not the root of the weld, the weld cap weld or bevel edge of the base metal hammering.
21, Hainan steel using the vibration method to eliminate stress, VSR process parameters and technical requirements should be consistent with current industry standard "welded components VSR process parameters and technical requirements," the relevant provisions of JB / T10375 in.