Hainan Steel tells you: Identification of welding steel engineering skills

1, the construction unit of the first choice of steel, welding materials, welding methods, joint way, welding position, post-weld heat treatment, a combination of various parameters and parameters should be in front of steel structure fabrication and installation of welding skills identification experiments. Experimental methods and welding skills identification requests, and exempted skills identified constraints, should be consistent with current national standard "steel welding standard" GB 50661 of the relevant provisions.
2, before welding construction, the construction unit should be qualified welding skills identification results or choose fit skills identified conditions for exemption based on the preparation of welding skills documents and should include the following:
(1) a combination of welding or soldering method;
Standard (2) of the base material, grade, thickness and coverage;
(3) Standard filler metal, type and model;
(4) welded joint way, beveling mode, the size and tolerance;
(5) welding orientation;
Species (6) welding power source and polarity;
(7) clean-treatment;
(8) Welding Skills parameters (welding current, welding voltage, welding speed, welding layer and bead distribution);
(9) road between preheating temperature and temperature range;
(10) after welding to eliminate stress handling skills;
(11) other necessary requirements.
Ⅱ welding work conditions
3, welding, workspace ambient temperature, relative humidity and wind speed should be consistent with the following provisions, when this provision exceeded and must be welded, shall prepare special programs:
(1) Operating ambient temperature should not be lower than -10 ℃;
(2) Relative humidity welding area should be greater than 90%;
(3) When the manual metal arc welding and flux cored arc welding from maintenance, welding work area maximum wind speed should not exceed 8m / s, while maintaining the gas arc welding work area should not exceed the maximum wind speed 2m / s.
4, site altitude welding work should erection firm operating platform and protective shed.
5, prior to welding, should use wire brushes, grinding wheels and other tools to remove be welded at the outer oxide scale, rust, oil and other debris, weld groove should be carried out according to the current national standard "steel welding standard" GB 50661 of the relevant provisions an examination.
6, welding welding skills should skills identification parameters.
7, when the welding temperature is below 0 ℃ and not lower than -10 ℃, heating or protective measures should be taken, should be welded joints and weld appearance in each direction is greater than or equal to 2 times the plate thickness within the range of not less than 100mm The base material is heated to a predetermined minimum preheat temperature not lower than 20 ℃ before welding. Hainan Steel
Ⅲ tacking
8, positioning weld thickness should not be less than 3mm, should not exceed 2/3 of the design throat thickness; length less than 40mm and joints four times the thickness of the thinner parts; spacing is preferably 300mm ~ 600mm.
9, positioning the weld seam with the official should have the same welding skills and welding quality requirements. Multi-channel positioning weld ends should be stepped. Selection steel liner plate welded joints, tacking should be carried out within the joint groove. Positioning welding preheat temperature should be higher than the official welding preheat temperature 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 ends of welded joints should be set arc weld plate, lead plate. Arc welding and gas metal arc welding seam maintain lead length should be greater than 25mm, submerged arc welding seam lead length should be greater than 80mm. Welding end and fully cooled, the choice of flame cutting, carbon arc gouging or mechanical methods such as removing the arc plate , leads to the plate and be grinding smooth. Do not use a hammer shot down.
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 plenty of fusion weld. When manual arc welding and gas metal arc welding maintenance, steel liner plate thickness should not be less than 4mm; when submerged arc welding, steel liner plate thickness should not be less than 6mm; when ESW steel liner plate thickness should not be less than 25mm.
Ⅴ between preheat and channel temperature control
13, preheat and channel temperature control should use electric heating, flame heating and infrared heating and other heating methods, and should be used in special thermometer measurements. Heating area should be preheated welding groove on both sides, the width should be the thickness of weldment welding at least 1.5 times, and not the less than 100mm. Temperature measurement point, when a non-member enclosed space, preferably in the weldment the back of the heating surface of the weld groove from both sides at no 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 current national standard "steel welding standard" GB 50661 of the relevant provisions; when the skills of selected preheating temperature lower than the current national standard "steel welding standard" GB 50661 The relevant provisions, should be determined by the skills identification experiments.
Ⅵ welding deformation control
15, the selection of welding skills and welding sequence should deformed components and shorten the minimum, the choice of welding deformation control following order:
(1) butt joints, T-joints and cross joints, in the case of component placement conditions allow or easily reversed, should be double-sided symmetrical welding; symmetrical cross-section of members, should be symmetrical to the member neutral axis welding; symmetrical connecting rods node element, the node should be symmetrical symmetry axis welding together;
(2) double-sided asymmetric groove welds are advised deep groove weld seam side section, full of light and then weld groove side, and finally the end of the deep groove side of the weld. Special plate should increase rotation symmetrical weld cycles;
(3) long seam welding method should be selected back-step, jump or more symmetrical welding method welding;
16, when members of a welding, soldering shorten set aside should use margin or pre shorten anti-deformation and deformation control method, shortening the balance and anti-deformation value should be determined by calculation or experiment.
17, when the member assembly welding, welding shortening should be larger joints, less shortening after welding joints, welding joints shall be binding in smaller states.
Ⅶ stress relieved after welding
18, design documents or the contract documents after welding to eliminate nodes or members stress there is a request and be subjected to tensile stress by fatigue check the structure of butt joints or welds clouds, should use electric heaters and partial annealing furnace annealing overall and other methods of stress relieving; when only stable structure size, the choice of the vibration method to eliminate stress.
19, heat treatment should fit the current industry standard "carbon steel, low alloy steel weld heat treatment after welding member," the relevant provisions of JB / T 6046 after welding. When selecting an electric heater welded components for local stress relief heat treatment, it should be consistent with the following provisions:
(1) is equipped with automatic temperature control device of the heating equipment, heating, temperature, temperature control performance should be consistent with the use of the request;
(2) members of each side of the heating plate welds (band) should be at least three times the width of the plate thickness, and not the less than 200mm;
Both sides of the member (3) An heating plate (with) suitably covered with insulating material.
20, with a hammer method to eliminate intermediate solder layer stress, you should use a hammer or a small round vibrating hand tools, should not have the root weld cap weld or weld groove edge of the base metal hammering.
21, the choice of the vibration method to eliminate stress, VSR skill parameters and the skills requested, should be consistent with the current industry standard "welded components VSR skill parameters and the skill request" JB / T 10375 of the relevant provisions. Hainan Steel