CN103990894A

CN103990894A - One-side-welding and two-side-forming welding technology for pipe

Info

Publication number: CN103990894A
Application number: CN201410242845.1A
Authority: CN
Inventors: 葛新波; 季小波; 陈鑫祎; 黄府; 刘珊珊
Original assignee: Nantong Zhong Yuan Heavy Industry Co Ltd
Current assignee: Nantong Zhong Yuan Heavy Industry Co Ltd
Priority date: 2014-05-29
Filing date: 2014-05-29
Publication date: 2014-08-20

Abstract

The invention discloses a one-side-welding and two-side-forming welding technology for a pipe. The welding technology comprises the main steps that first, the pipe is bottomed through manual argon arc welding, and second, a CO2 gas shield flux-cored wire is used for filling face covering, wherein the welding is performed from bottom to top, an ER70S-G argon arc welding wire with the length of 2.4 mm is adopted in the argon arc welding process, the current is controlled to range from 110 A to 130 A, the voltage is controlled to range from 10 V to 14 V, the diameter of a spraying nozzle is 10 mm, the gas flow is kept to be 12 L/min, an E71T-1 flux-cored wire with the length of 1.2 mm is adopted in the electrowelding process, the current is controlled to range from 150 A to 170 A, the voltage is controlled to range from 23 V to 27 V, the gas flow is kept to be 15 L/min, and the interlayer temperature is controlled to be lower than 200 DEG C. The welding method is high in efficiency and solves the problem that the back side of the pipe can not be welded; stretching, bending and impacting tenacity meets the AWSD1.1 standard requirement.

Description

A kind of welding procedure of single face welding and double face shaping of pipe

Technical field

The present invention relates to a kind of welding procedure, relate in particular to a kind of welding procedure for pipe.

Background technology

In prior art, be involved in the welding procedure of pipe single-side welding double-side forming, if publication number is that CN1672851A discloses a kind of not preheating of thick-wall red copper pipe butt weld single face welding and double face direct forming welding method.The method step is as follows: processing copper tube bevel for welding, worked copper nickel alloy fusing packing ring or alloy location chock; Before weldering, remove weld seam both sides dirt and oxide skin and use acetone wiped clean; Fusing packing ring or location chock are inserted to bevel for welding location; Adopt tungsten polar helium arc welding tack weld, backing weld seam and filling weld seam.The weldquality that this method is welded can meet the secondary quality requirement of national radioscopy standard GB3323-87, adopt special tungsten polar helium arc method, improve arc power and electric arc penetration ability, realize the not pre-thermal weld of thick-wall red copper 6-30mm, by adding the Ni of some and deoxidation Si, Mn alloying element in welding material, improve liquid weld metal surface tension, reduce liquid metal mobility, improve weld metal fusing point method, make welding forming good, strength of joint is high, plasticity good, has improved working environment simultaneously.

Although the method provides a kind of technique of pipe single-side welding double-side forming, the method is a kind of welding procedure for the body of thick-wall red copper material.For as also inapplicable in the pipe of the materials such as stainless steel, carbon steel.In actual demand, to the pipe welding of these materials, require very many, as there being a large amount of pipe splicing seams in mining machinery project, by general welding method, because tube interior face can not be soldered to, poor welding quality, can not meet the requirement of strength that welding designs.

Summary of the invention

Technical problem to be solved by this invention is to provide a kind of welding procedure of steel pipe, this technique can realize the object of single-side welding double-side forming, make pipe form linerless single welding full penetration weld, by the desired Non-Destructive Testing of ASW D1.1, mechanics and impact test.

In order to solve the problems of the technologies described above, the welding procedure of the single face welding and double face shaping of a kind of pipe of the present invention, comprises following steps:

A. first pipe side to be welded is processed to the groove of one 30 degree, and the inside and outside wall within the scope of polish groove face and 30mm thereof, make surface to be welded present metallic luster, by the groove 60 degree angles that are staggered relatively, root gap is controlled at 2.5mm to 3.5mm;

B. at horizontal level, use argon arc welding to position weldering on pipe to be welded, locate three places altogether along even circumferential, every director's degree is not less than 30mm, and positioning height is controlled at 2-3mm, needs polishing totally after completing tack welding;

C. first with argon arc welding, pipe is carried out to bottoming welding, during argon arc welding, need adopt 2.4mm ER70S-G argon-arc welding wire, Current Control in 110～130 peaces doubly, Control of Voltage is at 10～14 volts, nozzle diameter is selected 10mm, gas flow keeps 12L/min, the fixing welding from the bottom up of pipe level during welding;

D. use CO2 property of medicine welding wire to fill capping to pipe, now adopt 1.2mm E71T-1 flux-cored wire, Current Control in 150～170 peaces doubly, Control of Voltage is at 23～27 volts, gas flow keeps 15L～20L/min, interlayer temperature is controlled at below 200 degree, the fixing welding from the bottom up of pipe level during welding.

The body of optimum Q345B material in above-mentioned process, especially pipe.

This welding method bottoming welding adopts argon arc welding, has guaranteed the quality of the root of weld, solves the problem that pipe reverse side cannot be welded to; Cap weld adopts flux-cored arc welding, has improved the welding job efficiency of a large amount of workpiece.The pipe that utilizes also welding procedure welding postwelding within 24 hours, carry out by AWS D1.1 standard carry out VT, UT, MT detects, and stretches, crooked, impact ductility test, all meet the requirements.

Accompanying drawing explanation

Fig. 1 is pipe butting grooves figure

Fig. 2 is tube welding directional diagram

The specific embodiment

The present invention be take mother metal as Q345B material, pipe is that example is elaborated.

1 welding method

Because argon arc welding bottoming has lot of superiority, can not only fully guarantee the good penetration of mother metal root, thereby avoid producing root crack, in welding, be not prone to the defects such as lack of penetration, slag inclusion, pore yet.This technique is used manual argon arc welding bottoming.

Consider that on-the-spot tubing abutment joint is more, as full use argon arc welding welding, efficiency is too low simultaneously, therefore select CO2 gas-shielded flux-cored wire to fill capping.

2 wldings

According to etc. strong matching principle use the bottoming of 2.4mm ER70S-G argon-arc welding wire, use 1.2mm E71T-1 flux-cored wire to fill capping.

3 grooves are prepared

By pipe side machining 30 degree grooves to be welded, see accompanying drawing 1.

4 preweld cleanings

Before pipe fitting assembling, need the iron rust within the scope of groove face and internal and external walls 30mm, greasy dirt etc. to remove by polishing, oven dry, make surface to be welded present metallic luster, welding as early as possible after cleaning.

The assembling of 5 pipe fittings

By the alignment of the auxiliary pipe fittings such as channel-section steel, at mean place, use argon arc welding to position weldering, along even circumferential, locate three places altogether, every director's degree is not less than 30mm, and positioning height should be controlled at 2-3mm, and after tack welding, polishing is clean.Consistent when wlding that tack welding uses, welding parameter should be with formal welding, because tack welding will incorporate final weld seam, therefore must penetration, must not there be the defects such as pore, crackle, slag inclusion to exist, if any, reorientate after needing polishing to remove weld seam.

6 welding

6.1 welding equipment

GTAW is used WSM-400 type welding machine, straight polarity direct current, and the protection of front pure argon, tungsten electrode model is EWTH-22.4mm.

XD500SII type welding machine is used in the welding of CO2 property of medicine welding wire, and DC reverse connection, is used pure CO2 gas shield.

6.2 welding process

6.2.1 welding parameter is with reference to following table.

6.2.2 weld main points

Manual argon arc welding is used interrupted wire feed, mainly by advance and time delay supply gas to prevent weld seam start-stop two ends gas protection deficiency, prevent emergent gas protection zone, welding wire end and be oxidized.After welding starts, should first with electric arc, pipe groove root be heated, behind molten bath to be formed, at once add welding wire, it is slow that at this moment weldering speed is wanted, and add a little welding wires, thickeies weld seam in case crack arrest line.Weld completely, electric current should reduce gradually, and electric arc is slowly transferred on groove and extinguished, and does not allow in the unexpected current interruption in weld seam center, and one side cracks, and stops protection, prevents weld seam oxidation.During welding, to map out the length of welding wire, avoid repeatedly changing silk midway, to reduce the number of times of " cold junction ".

During welding, circumference is divided into two sections, welding from the bottom up, as shown in Figure 2.

First weld seam after bottoming is answered quick and stable, prevents that prime coat from burning.

Control interlayer temperature below 200 ℃.

If find defect in welding process, should stop at any time, after polishing repair welding are good, continue again welding.

7 postweldings detect and test

Postwelding carries out carrying out VT, UT, MT by AWS D1.1 standard for 24 hours and detects, and acceptance criteria is with reference to AWS D1.1 the 6th chapter, and stretch, crooked, impact ductility test, all meet the requirements.

Claims

1. a welding procedure for the single face welding and double face shaping of pipe, is characterized in that comprising following steps:

2. the welding procedure of the single face welding and double face shaping of a kind of pipe as claimed in claim 1, is characterized in that described pipe is Q345B material.

3. the welding procedure of the single face welding and double face shaping of a kind of pipe as claimed in claim 2, is characterized in that described pipe pipe.

4. the welding procedure of the single face welding and double face shaping of a kind of pipe as claimed in claim 3, is characterized in that described argon arc welding is manual GTAW.