What are the requirements for groove welding, and what is the function of welding groove?

Preparation and welding process for groove welding.

The following requirements should be met:

The bevel surface should be smooth, and there should be no cracks, blunt edges, and missing edges at the edge of the incision.

The bevel angle can be selected according to the data.

The thickness of the steel backing plate should be 4 6mm, and the length should be 40 60mm. When flat welding, the width of the backing plate should be the diameter of the steel bar plus 10mm; When vertical welding, the width of the backing plate should be equal to the diameter of the steel bar.

The width of the weld should be greater than the edge of the V-groove 2

3mm, weld residual height.

It should not be larger than 3mm and smoothly transition to the surface of the rebar.

Between the steel bar and the steel backing plate, welding 2 should be added

3 layers of side welds.

When it is found that there are arc pits, pores and undercuts in the joint.

and other defects, should be repaired immediately.

Welding groove processing method:

1) Trimming: shearing with shearing machine, often used for I-shaped groove.

2) Planing: It is processed by planer or planing machine, and is often used for plate processing.

3) Turning: Processed with a lathe or tube turning machine, suitable for pipe processing.

4) Cutting: Cut by hand with oxygen-acetylene flame or cut by automatic cutting machine into I-shaped, V-shaped, X-shaped and K-shaped grooves.

5) Carbon arc gouging: It is mainly used for slotting when cleaning the welding root, with high efficiency and poor working conditions.

6) Shoveling or grinding: Shoveling with manual or pneumatic, electric tools or grinding with a grinder (or angle grinder) for grinding processing, the efficiency is low, and it is mostly used for slotting of welding defect repair parts. The quality of bevel processing has a great impact on the welding process, and it should meet the requirements of drawings or technical conditions.

Requirements for welded bevels:

1) Minimize the amount of filler metal.

2) The bevel shape is easy to process.

3) It is convenient for welders to operate and remove slag.

4) The stress and deformation after welding are as small as possible.

When the thickness of the weldment is equal to or large or the multi-layer multi-pass welding method is 6mm, because the heat of the arc is difficult to make the root of the weld penetrate, it should be beveled or multi-layer multi-pass welding.

In order to ensure the quality of welding, the processing of the workpiece that needs to be welded before welding can be gas cut or cut, generally beveled, sometimes curved surface. For example, two steel plates with a thickness of 10mm should be welded together, and in order to make the weld firm, Huiqing will mill the chamfer at the edge of the plate, which is called beveling. Due to the different material thickness and welding quality requirements, the form of the welded joint and the shape of the groove are not the same, and the general groove form is divided into K type, V type, I type, U type, X type, etc.

Below 6mm, there is no need to open the bevel, but the back should be cleaned to ensure the quality of welding. If it is more than 6mm, it is best to open the groove, and it is difficult to weld through if it is not silver, and the non-destructive testing will not be qualified. In fact, I personally suggest that it is best to open the groove regardless of the thickness of the roll, and carry out argon arc welding to ensure the quality of welding, reduce the repair rate, and improve the pass rate and production efficiency of welding.

Summary. Hello, specific reference: GB 985-88 basic form and size of weld groove of gas welding, manual arc welding and gas shielded welding, GB 986-88 basic form and size of groove of submerged arc weld.

2. Manual arc welding should be in line with the national standard "carbon steel electrode" (GB T5117) or "low alloy steel electrode" (GB T5118) The groove size of the electrode weldment is related to the welding method and plate thickness. Generally, the groove angle of hand arc welding is 40-60 degrees, and the larger the plate thickness, the smaller the angle. The common 10-20mm steel plate has a groove angle of roughly 55-60 degrees.

What is the standard for welded grooves on steel plates.

Hello, specific reference: GB 985-88 gas welding, manual arc welding and gas shielded welding weld groove basic form and size, GB 986-88 submerged arc welding weld groove basic form and size 2, manual arc welding should be in line with the national standard "carbon steel electrode" (GB T5117) or "low buried alloy steel electrode" (GB T5118) specified in the electrode weldment groove size and welding method, plate thickness related. Generally, the groove angle of hand arc welding is 40-60 degrees, and the larger the plate thickness, the smaller the angle.

The common 10-20mm Youlishi steel limb plate has a groove angle of about 55-60 degrees.

The following is the standard type of steel plate welding groove: Process content: Clean up the slag and iron oxide after semi-automatic or manual cutting, and then use a grinder or grinder to smooth the rolling cut, and by the way, polish both sides of the cutting place until the metallic luster is exposed, and have assembly and welding conditions.

The main functions of the welding groove are as follows:

1. Ensure that thicker plates or other structures can be welded through and fused well. The arc can penetrate deep into the root of the weld, so that the root can be welded through, and the blunt edge is to prevent burn-through, but the size of the blunt edge should ensure that the first layer of welding can be welded through.

2. Adjust the welding heat input.

3. Improve the strength of weld joints.

Hello. The purpose of the weld groove is: Because the iron plate is too thick. This may result in direct welding of wood. That's the purpose of beveling. In order for us to be able to weld the iron plate through directly. At the same time, it is also to increase the strength of our welds.

Precautions for welding grooves.

1. When the electrode arc is welded, in order to ensure that the electrode can be close to the root of the joint and can be fused well on the side during multi-layer welding, the root gap must be increased when the groove angle is reduced.

Note that the former is reduced, and a smaller amount of filler metal can be used. The latter increases, but the amount of filler metal increases. It is found that when the plate thickness is δ 20mm, it is economical to use a small root gap with a large bevel angle, δ and to use a small bevel angle with a large root gap at 20mm.

2. The root gap is too small, the root is difficult to penetrate, and the welding rod with a smaller specification must be used, so as to slow down the welding process; If the root gap is too large, although the application of liner can ensure the quality of the weld, more filler metal is required, which increases the welding cost and increases the welding distortion.

3. Due to the thin wire and the use of special contact tips, the butt welding of the narrow gap (10mm) of the L-shaped groove of the thick plate (200mm) can be realized.

4. The joint of the bevel, the groove without leaving a blunt edge is called a sharp groove, and it is easy to burn through when welding the first layer of the weld bead without a liner on the back, and more filler metal is required, so the blunt edge is generally left. The height of the blunt edge is to ensure both penetration and non-burn-through.

The blunt edge of the V-shaped or U-shaped groove of the electrode arc welding is generally 0 3mm, and the double-sided V or U-shaped groove is 0 2mm. The penetration depth of submerged arc welding is larger than that of electrode arc welding, so the blunt edge can be appropriately increased to reduce the filler metal.

For joints with blunt edges, the size of the root gap is mainly determined by the welding process and welding position. On the premise of ensuring weld penetration, the gap is as small as possible. In the case of flat welding, a large welding current can be allowed, and the root clearance can be zero; The root gap should be larger during vertical welding, and it can be more than 3mm when welding thick plates.

In the single-sided back-forming operation, the root gap is generally large, about the same as the diameter of the electrode used. When there is a permanent liner on the back, the blunt edge should be eliminated because it will reduce the fusion between the root of the joint and the gasket.

5. The root radius is often made on the J-shaped or U-shaped groove, mainly in order to close the root of the weld in the deep groove and reduce the cooling rate of the first layer of the weld bead to ensure good fusion and forming of the root.

When the electrode arc is welded, the root radius is generally taken as r=6 8mm, which increases appropriately with the increase of plate thickness and the decrease of groove angle.

6. If conditions permit, the plate thickness structure should be designed or selected double-sided bevel weld, double-sided V-shaped weld not only uses half less filling material than single-sided V-shaped weld, but also can be welded alternately on both sides to control the welding angle to a minimum.

7. The butt joint without liner on the back often has defects such as unwelded penetration or inclusions in the blunt edge, and it is generally required to clean the root from the back. Now the carbon arc gouging method is widely used to clear the roots. The depth of root cleaning should ensure that the weld metal is exposed without defects, and the shape of the groove profile after root cleaning should be easy to weld.

Bevel welding is to weld on a machined groove with the usual welding device.

According to the design or process needs, the groove of a certain geometric shape that is processed and assembled at the part to be welded in the weldment is called groove. The groove is mainly for welding the workpiece, to ensure the degree of welding, under normal circumstances, the profile processed by the machining method, when the requirements are not high, it can also be gas cut (if it is a type of weld, ultrasonic flaw detection is required, then only the machining method can be used), but the oxidation slag needs to be removed, according to the need, there are K-shaped grooves, V-shaped grooves, U-shaped grooves, etc., but most of them are required to retain a certain blunt edge.

Before the construction of groove welding, a groove is formed at the end of the welded steel bar. The bevel surface should be smooth, and there should be no cracks, blunt edges, and missing edges at the edge of the incision. When the groove is flat welding, the groove angle should be 55° 65°; When the groove is vertical welding, the groove angle should be 40° 55°, wherein, the lower steel bar should be 0° 10°, and the upper steel bar should be 35° 45°.

The gap between the roots of the steel bar should be 4 6mm when the groove is flat welding: 3 5mm when vertical welding. The maximum clearance should not exceed 10mm.

The thickness of the steel backing plate should be 4 6mm, and the length should be 40 60mm. When groove flat welding, the width of the backing plate should be the diameter of the steel bar plus 10mm, and the width of the backing plate should be equal to the diameter of the steel bar during vertical welding.

When the bearing force is large, you need to open the opening! The main thing is to weld through! Guaranteed welding quality!

Welded joint form: butt joint, corner joint and T-shaped joint, lap joint.

Welding groove - in order to ensure full penetration and welding quality, and reduce welding deformation, the weldment connection is generally pre-processed into various shapes before welding.

Different welding grooves for different welding methods and weldment thicknesses.

Bevel shape. Basic bevel shape:

shape, V-shaped, unilateral V-shaped,

U-shaped, J-shaped.

, welded joint type.

In manual arc welding, the joint type is different due to the thickness of the weldment, the shape of the structure and the quality requirements.

According to the national standard GB9

85-80 stipulates that the types of welded joints can be mainly divided into four types, namely butt joints, corner joints, lap joints, and T-joints).

1. a butt joint.

The joint with two weldment ends facing each other is called a butt joint, which can bear a large load and is the most commonly used joint in welded structures.

2 Corner joints.

The joint between the end faces of the two weldments is greater than 30 ° and less than 135 ° is called the angle joint, and the angle joint is mostly used in box-shaped components, and the bearing capacity of the weld is not high, so it is generally used in the unimportant welded structure.

3 Lap joints.

The end joint composed of two weldments overlapping or the angle between the two weldment surfaces is not more than 30 ° is called lap joint, the stress distribution of lap joint is uneven, the bearing capacity of joint is low, and the tower joint should be avoided as much as possible in structural design.

4 T-joints.

The joint that the end face of one weldment and the surface of another weldment form a right angle or an approximate right angle is called a T-joint, which is more commonly used in the welding structure, and the whole joint bears the load, especially the ability to bear the dynamic load.

Second, the role and form of the groove.

According to the needs of the design or process, the part to be welded in the weldment is processed into a certain geometric shape.

The groove is called the groove.

1. The role of the groove.

Its main function is to ensure the penetration of the weld root, so that the welding heat source can penetrate deep into the root of the joint, so as to ensure the quality of the joint. The bevel also plays a role in adjusting the ratio of base metal to filler metal.

2. The size name and marking of the groove.

The blunt edge is to prevent burn-through, and the blunt edge size should ensure that the first layer of weld is welded through. When the root gap is primed, it can ensure that the part is welded through. The groove angle is used to make the arc penetrate deep into the root of the weld, so that the blunt edge is welded through, and it is easy to remove the slag to obtain an aesthetically pleasing weld.

3. Common groove forms.

Commonly used groove forms include I-shaped groove, Y-shaped groove, U-shaped groove with blunt edge, double Y-shaped groove, unilateral V-shaped groove with blunt edge, etc.

4. Selection of welding groove.

The selection of weld grooves generally follows the following principles:

It can ensure the welding penetration of the workpiece, (the penetration depth of hand arc welding is generally 2 4mm), and it is convenient for welding operation. If it is inconvenient to weld inside the container, a single-sided groove should be used to weld on the outside of the container.

The bevel shape should be easy to machine.

Maximize welding productivity and electrode savings.

Minimize the deformation of the workpiece after welding.

The following are the steel plate welding groove standards:

Process content: clean up the slag and iron oxide after semi-automatic or manual cutting, and then use a grinder or grinder to smooth the cutting place, and by the way, polish both sides of the cutting place until the metallic luster is exposed, and have assembly and welding conditions.

GB 50236-2011 Appendix C, The standard for welded bevels is GB 50236-2011, see Appendix B of this standard for details.

Groove welding refers to the welding process that is processed into a certain geometric groove in the part to be welded in the weldment according to the design or process requirements.

Bevel welding is performed with the usual welding device, resulting in a wide shielding gas laminar flow layer that effectively protects deep narrow groove welds and is stable enough to complete the weld cap.

Before the construction of slope hole cleaning welding, the groove is formed by the incision at the end of the welded steel bar. The bevel surface should be smooth, and there should be no cracks, blunt edges, and missing edges at the edge of the incision. When the groove is flat welding, the groove angle should be 55 degrees to 65 degrees; When the groove is vertical welding, the groove angle should be 40 degrees to 55 degrees.

Among them, the lower steel bar should be 0 degrees to 10 degrees, and the upper steel bar should be 35 degrees to 45 degrees. The gap between the roots of the steel bar, the groove is 4 to 6 mm when the groove is flat welded; It should be 3 to 5 mm for vertical welding. The maximum clearance should not exceed 10 mm.

The thickness of the steel backing plate should be 4 to 6 mm, and the length should be 40 to 60 mm. When groove flat welding, the width of the backing plate should be the diameter of the steel bar plus 10 mm, and the width of the backing plate should be equal to the diameter of the steel bar during vertical welding.