How to connect galvanized steel pipes? Welding process control method?

Steel pipe is a common material in our life, and now there are more and more kinds of materials on the market. Now I trust galvanized steel pipes. Galvanized steel pipes have good corrosion resistance in steel pipes, so they are welcomed by many consumers. Next, we will introduce how to connect galvanized steel pipes and how to control the welding process. Steel pipe is a common material in our life, and now there are more and more kinds of materials on the market. Now I trust galvanized steel pipes. Galvanized steel pipes have good corrosion resistance in steel pipes, so they are welcomed by many consumers. Next, we will introduce how to connect galvanized steel pipes and how to control the welding process.

First, how to connect galvanized steel pipes

1, automobile wire connection

(1) Thread disorder: The coupling and thread can't completely contact or loosen, so cut off the disordered thread and reinstall the thread.

(2) The thread of the steel pipe is inconsistent with the thread of the pipe hoop and cannot be connected. The pipe hoop should be replaced or the adjusting equipment should be re-threaded.

(3) Leakage printing after steel tube car line: Measure whether the wall thickness of steel pipe can meet the standard thickness requirements of line turnover pipe.

2. Welding joint

(1) The nozzle of the steel pipe is not in a straight line after butt joint, and the steel pipe has an oblique mouth. It is suggested that the steel pipe head be cut off in a short time before processing.

(2) After the steel pipe nozzles are butted, the two nozzles are not tightly butted, resulting in uneven thickness of the welded joint; As well as the elliptical nozzle of the steel pipe caused by its own reasons or transportation bumps, it is suggested that the pipe head of the steel pipe be cut off for a short time before processing.

(3) After the steel pipe nozzle is docked, sand holes appear at the pipe nozzle:

1, due to technical reasons during welding.

2. There are zinc nodules on the nozzle, which causes welding difficulties and sand holes. Only zinc particles need to be removed from too large and too many pipes.

3, rolling groove connection

(1) Cracking of rolling groove weld:

1. Smooth the weld on the inner wall of the nozzle groove pressing part to reduce the rolling resistance of the groove.

2, adjust the axis of the steel pipe and rolling equipment, and require the steel pipe and rolling equipment level.

3. Adjust the pressure groove speed, so that the pressure groove forming time does not exceed the specified time, and the force is even and slow.

(2) Fracture of slotted steel pipe:

1. Smooth the welding rib on the inner wall of the groove of the steel pipe mouth to reduce the rolling resistance of the groove.

2. Adjust the axes of steel pipes and grooving equipment to ensure that the steel pipes and grooving equipment are horizontal.

3, adjust the pressure groove speed, pressure groove speed can't exceed the prescribed, evenly and slowly.

4. Check the width and model of the backup roller and the pressure roller of the grooving equipment to see if there is any biting phenomenon caused by the mismatch of the sizes of the two rollers.

5. Use vernier caliper to check whether the groove of steel pipe meets the requirements.

(3) The groove formed by rolling with a grooving machine shall meet the following requirements:

1. The surface from the pipe end to the groove section shall be smooth without unevenness and rolling marks.

2. The groove center should be concentric with the pipe wall, and the groove width and depth meet the requirements, and check whether the clamp model is correct.

3. Apply lubricant to the rubber sealing ring and check whether the rubber sealing ring is damaged. Oil lubricant is not allowed as lubricant.

Second, the welding process control

The preparation of galvanized steel before welding is the same as that of ordinary low carbon steel, and attention should be paid to the groove size and the nearby galvanized layer. For penetration, the groove size should be appropriate, generally 60 ~ 65? , to leave a certain gap, generally1.5 ~ 2.5 mm; In order to reduce the penetration of zinc into the weld, the galvanized layer in the groove can be removed before welding.

In the actual supervision work, centralized groove is used for centralized control, and the double-layer welding process reduces the possibility of incomplete penetration.

Covered electrode should be selected according to the matrix material of galvanized pipe, and J422 is mostly used for low carbon steel for operability.

Welding technology: When welding multi-layer welds, try to melt and vaporize the zinc layer to escape from the weld, which can greatly reduce the residual liquid zinc in the weld.

When welding fillet weld, try to melt the zinc layer in the same layer to make it evaporate and escape from the weld. The method is to move the covered electrode tip forward about 5 ~ 7 mm first, and then return to the original position to continue welding after the zinc layer is melted.

When welding horizontally and vertically again, if a short slag covered electrode like J427 is selected, the tendency of undercut will be very small; If reciprocating rod conveying technology is adopted, defect-free welding quality can be obtained.

The above is all the knowledge about how to connect galvanized steel pipes and how to control the welding process. I hope I can help you. How to connect galvanized steel pipes must be known to the owner before construction.

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