Welding Auxiliary Equipment: Introduction of Various Fixtures

The tools used for arc welding, such as welding tongs and masks for electrode arc welding, welding torches for gas shielded welding, etc., have been explained in specific chapters, and only welding fixtures are introduced in this section. Requirements for welding fixtures:

1. The welding fixture should ensure the correctness of the size and shape of the assembly.

2. Welding fixtures should be light and convenient for clamping and dismounting, and should not hinder the welding operation and affect the welder's vision observation range, and improve the efficiency of weldment assembly.

3. Welding fixtures should be clamped reliably, with appropriate rigidity, neither loosen the weldment nor produce excessive restraint, so as to reduce welding stress and prevent welding deformation.

4. The welding fixture should be simple in structure, convenient to manufacture, safe and convenient to use and adjust.

Common welding fixture

Locator : The fixture used to make the weldment reach a certain position during assembly and welding is called a locator. The locator is usually very simple, and depending on the product, it is mainly made by yourself. The positioner includes a stopper, a positioning pin, a V-shaped iron and so on.

1. Stop iron positioning: properly arrange angle steel, rectangular plate, etc. on the periphery of the welded device or part, so that the weldment can be positioned in the horizontal or vertical plane, as shown in Figure 1 and 2 below. This is the simplest positioning method, but its accuracy is not high.

2. Locating pin positioning: The locating pin uses the machined holes on the part for positioning, and the accuracy is high, as shown in 3 in Figure b. This locating pin can not only control the angle between the two profiles, but also ensure the accuracy. V-shaped iron is often used for fixing and positioning cylindrical parts such as pipes, shafts and small tube sections.

3. V-shaped iron positioning: V-shaped iron is often used for fixing and positioning cylindrical parts such as pipes, shafts and small diameter cylindrical sections, as shown in Figure c. The notch angle of the V-shaped iron is usually 90° or 120°.

Clamping tool : The clamping tool is used to fix the position of the compression weldment during assembly and prevent it from moving during the welding process. Common clamping tools are shown in the figure below, which are used to fasten assembly parts.

The typical application form of screw clamp is shown in the figure below.

Pneumatic clamps and hydraulic clamps are also widely used in batch or mass production, and in many forms, they can not only clamp the workpiece, but also control and correct the deformation of the weldment. The following picture shows the application of pneumatic clamp.

Tension and push support clamps : There are three types of tension and push support clamps : jack, tensioner and push supporter.

1. Jack: used to bear the quality of the weldment, and as a supporting surface or push-clamp weldment. The deformation of beams and columns of large welded structural parts is often corrected with jacks.

2. Push support: In the welding process, it is often necessary to correct the shape of the weldment, eliminate the butt deviation and prevent the deformation during the welding process. For example, in order to eliminate ellipses, depressions and other similar defects in welded cylindrical sections and cylindrical products, an annular pusher with several radially arranged spiral jacks can be used (as shown in the figure a below), which is 15mm thick. The following correction of the cylindrical wall is an effective means.

Tensioner: Tensioner is an auxiliary tool to tighten two or more components during assembly. The spiral tensioner used to tighten the weldment in the production is shown in Figure b and c above. The tensioner consists of two push rods with left-hand and right-hand threads and a middle connector.