Generally speaking, sheet metal processing is a comprehensive cold working process for metal sheets with a thickness of less than 6 mm, which includes cutting, punching, cutting, compounding, folding, welding, riveting, splicing and forming. Among them, welding is a very important link. There are some problems needing attention in metal welding in sheet metal processing before welding, during welding and welding standards. Let's sum up:

Requirements before welding of sheet metal parts

First of all, all the raw materials of sheet metal parts shall not be lower than the requirements of the drawings, otherwise they cannot be cut and made;

Secondly, it is required that the surface flatness of welded section steel should not exceed two thousandths, and the total curvature should not be greater than 0.3% of the total length;

Moreover, before welding sheet metal parts, all deformed spare parts must be straightened and leveled before welding;

Finally, before welding starts, to choose a suitable welding wire, welding wires with different thickness and specifications must be selected according to different parameters such as part size, material thickness and weld requirements.

Requirements in welding process of sheet metal parts

First of all, the welding process must be carried out in strict accordance with the requirements of drawings, technology and process. If the workpiece is welded incorrectly because of the wrong drawing, and it must be re-welded, the workpiece can only be treated as defective;

Secondly, when welding, it is required that the groove must be machined at the place where the groove is machined. If the machined part has no groove or welded profile, the groove should be machined by polishing machine or mechanical processing means according to the situation;

Third, when welding, ensure that the overall dimensions and form and position tolerances of the workpiece meet the requirements of the drawings, and the form and position tolerances of non-machined surfaces shall be implemented according to IT15 level without special requirements;

Fourth, if you need to substitute materials during welding, you must obtain the written consent of the technical department, and the thickness of the sheet must meet the requirements of the drawings, otherwise you can't substitute materials;

Fifthly, the weld size during welding must be strictly in accordance with the requirements of the drawings. Intermittent welding cannot be used for this continuous welding, and vice versa. If the drawings do not explicitly require the size and length of intermittent welding, it should be carried out according to the welding of 8 to 10 mm at intervals of 50 mm, and the distance between each welding spot must be uniform;

Sixth, the continuous weld must be straight and smooth, and there must be no obvious uneven phenomenon, and there must be no phenomena such as welding penetration, welding deviation, welding scar, porosity and undercut. The welding angle of the weld shall be subject to the requirements of the drawings, and there is no requirement to ensure that the welding angle is the minimum thickness of the adjacent parts;

Seventh, after welding is completed, each weld should be polished, which can not only remove welding slag, but also remove the surrounding burrs;

Eighth, some parts should not be welded, for example, parts that require bending on drawings should not be welded without the written consent of the technical department;

Ninth, in the welding process of sheet metal parts, the parts that need to be hammered can be lightly hammered with a small hand hammer until the size meets the requirements, and the parts must not be hammered vigorously on the sheet metal plane, otherwise the workpiece will be damaged and scrapped.

Requirements and standards for post-welding treatment of sheet metal parts

First of all, the weld seam of sheet metal parts is required to be smooth and fish-scale-like, and convex hull and uneven phenomenon are not allowed;

Secondly, the edge of the workpiece must be flush and flat. After welding, it must be polished again with emery cloth to remove the residual welding slag, welding spots and burrs at the edges and corners with thorns, and keep the weld flat and smooth.

Thirdly, on the plane of box-like workpiece, the height of weld should not be higher than the plane height, and in principle, the weld should be completely covered after putty is applied;

Fourthly, for revolving parts and planes that need not be processed after welding, strict protection must be carried out during welding to avoid arc damage or slag damage, and polishing can not be carried out casually on the premise of uniform weld;

Fifthly, for the metal parts that need to be blued and electroplated after welding, after the welding meets the requirements, they should be uniformly sandblasted, and they should be strictly protected during the turnover process to avoid bumps and scratches, and they should not be polished again.

Article source: Hook net