CN105750705A - Heat-resisting steel pipe welding technology - Google Patents

Abstract

The invention discloses a heat-resisting steel pipe welding technology characterized by comprising the following steps of (1) selecting a method, (2) selecting a single-sized V-shaped groove, (3) grinding places20 to 30mm of inside and outside of pipes on two sides of the groove before welding until metallic luster shows, (4) pre-heating before welding, (5) including (1) conducting backing weld via argon arc welding, (2) conducting filling welding via shielded metal arc welding, (3) conducting cover-surface welding via shielded metal arc welding, (6) employing warming material to cover and warm a welding joint and a joint near area after welding is finished, so the joint can be slowly cooled. In the (1) step, manual argon tungsten-arc welding is employed for backing welding and welding technology methods of manual arc welding filling and cover-surface welding are employed; in the (5) step, welding current is slightly smaller than current of a filling layer; a correct welding bar angle is selected; electrode manipulation is even, so undercut deficiency can be prevented on the edge of the grove; a surplus height of the welding joint is controlled to be 1 to 3mm, so stress production can be prevented for the welding joint during the use; in the (6) step, a welding member is heated to 720 to 760 DEG C on the whole and the temperature is remained for 1 to 2 hours; then the welding member is cooled to the indoor temperature via a furnace. The welding technology is simple, has great welding effect and high welding quality.

Description

A kind of heat resisting pipe welding procedure

Technical field

The present invention relates to a kind of heat resisting pipe welding procedure.

Background technology

Current heat resisting pipe welding procedure is more complicated, also without unified specification, it does not have unified standard, the heat resisting pipe quality causing production is uneven, a lot of operations that repeat also make under production efficiency, increase the work burden of workman, make the competitiveness of product in market not high simultaneously.For some operators just entered a profession, it does not have a clear and definite method technique, cause, when operation, mistakes and omissions often occur, in some instances it may even be possible to cause serious consequence.Summary of the invention

Because the drawbacks described above of prior art, the technical problem to be solved is to provide a kind of heat resisting pipe welding procedure, and this welding technique is simple, and welding effect is good, and welding quality is high.

For achieving the above object, the invention provides a kind of heat resisting pipe welding procedure, it is characterised in that comprise the steps, 1) method selection, adopt GTAW bottoming, the welding technique of manual electric arc welding filling and capping；2) select one side V-butt, mechanically process, should strictly control root gap and root face size, to guarantee the thorough penetration of backing weld seam；

3) each 20～30mm scope inside and outside the pipe of groove both sides should be polished totally before weldering, until exposing metallic luster, it is ensured that without oil stain, rust, moisture content, oxide or other harmful materials；Argon arc welding welding wire surface must not have the dirt such as oils and fats, rust；The welding rod of arc welding, must dry 1～2h through 350～400 DEG C before weldering, and deposit at 120 DEG C of heat-preservation cylinders, ready access upon use；Adopting 3～4 pieces of wedge type blocks to be Distribution and localization and be welded on groove, docking port must be concordant, and unfitness of butt joint cannot be greater than 0.5mm, and the wlding of tack welding and welding parameter are identical with formal welding, and positions weldering when preheating；

4) weld preheating: selecting preheating temperature is 200～300 DEG C, and preheated zone is centered by weld seam, and both sides are at least 100mm；In whole welding process, interlayer temperature should be kept to be not less than preheating temperature；

5) (1) bottom argon arc welding weldering；Being in by pipe fitting and horizontally rotate position welding, adopt short arc during welding, welding gun is vertical with surface of the work as far as possible, is conducive to the argon protection to welding pool；Welding gun and welding wire can slightly do teeter, it is ensured that groove both sides penetration；Meanwhile, bath temperature of controlling well prevents burn-through and welded tumour defects；At joint area, with portable grinder buffing arc crater, the weld defects such as the receipts burst check stricture of vagina at arc crater place and pore are removed, then proceed to striking welding；(2) SMAW fills weldering；Short arc should be adopted to weld, and heat input is unsuitable excessive；Weld according to long arc, not only there will be that arc burning instability, fusion penetration are shallow, fusing splatter is big and the problem such as alloying element scaling loss aggravation, and easily producing undercut, the defect such as lack of penetration, the harmful gas such as N2, O2 in air easily enters molten bath simultaneously, forms gas hole defect in weld seam；During welding, welding rod can make little crescent arc manipulation, to stop 0.5～1S in groove both sides, welding interlayer must thoroughly clear up welding slag, it has been found that when having the weld defects such as pore, arc crater must be filled up when weld defect being removed and received arc with portable emery wheel, in order to avoid producing crater crack；The joint of each interlayer should stagger, and must not have overlap；(3) SMAW cosmetic welding；Welding current is more slightly smaller than packed layer, should select correct welding rod angle, and arc manipulation is wanted uniformly, it is prevented that produce undercut defect in bevelled edge；Weld reinforcement to control at 1～3mm, it is to avoid welding point in use produces stress and concentrates.

6) when welding terminates, insulation material should be adopted immediately by weld seam and Jin Feng district covering and heat insulating, make joint Slow cooling, subsequently, then weldment entirety be heated to 720-760 DEG C, after constant temperature 1～2h, cool to room temperature with the furnace.

The invention has the beneficial effects as follows: the welding technique of the present invention is simple, and welding effect is good, welding quality is high.

Detailed description of the invention

Technical scheme disclosed by the invention is a kind of heat resisting pipe welding procedure, it is characterised in that comprise the steps, 1) method selection, adopt GTAW bottoming, the welding technique of manual electric arc welding filling and capping；2) select one side V-butt, mechanically process, should strictly control root gap and root face size, to guarantee the thorough penetration of backing weld seam；

3) each 20～30mm scope inside and outside the pipe of groove both sides should be polished totally before weldering, until exposing metallic luster, it is ensured that without oil stain, rust, moisture content, oxide or other harmful materials；Argon arc welding welding wire surface must not have the dirt such as oils and fats, rust；The welding rod of arc welding, must dry 1～2h through 350～400 DEG C before weldering, and deposit at 120 DEG C of heat-preservation cylinders, ready access upon use；Adopting 3～4 pieces of wedge type blocks to be Distribution and localization and be welded on groove, docking port must be concordant, and unfitness of butt joint cannot be greater than 0.5mm, and the wlding of tack welding and welding parameter are identical with formal welding, and positions weldering when preheating；

4) weld preheating: selecting preheating temperature is 200～300 DEG C, and preheated zone is centered by weld seam, and both sides are at least 100mm；In whole welding process, interlayer temperature should be kept to be not less than preheating temperature；

5) (1) bottom argon arc welding weldering；Being in by pipe fitting and horizontally rotate position welding, adopt short arc during welding, welding gun is vertical with surface of the work as far as possible, is conducive to the argon protection to welding pool；Welding gun and welding wire can slightly do teeter, it is ensured that groove both sides penetration；Meanwhile, bath temperature of controlling well prevents burn-through and welded tumour defects；At joint area, with portable grinder buffing arc crater, the weld defects such as the receipts burst check stricture of vagina at arc crater place and pore are removed, then proceed to striking welding；(2) SMAW fills weldering；Short arc should be adopted to weld, and heat input is unsuitable excessive；Weld according to long arc, not only there will be that arc burning instability, fusion penetration are shallow, fusing splatter is big and the problem such as alloying element scaling loss aggravation, and easily producing undercut, the defect such as lack of penetration, the harmful gas such as N2, O2 in air easily enters molten bath simultaneously, forms gas hole defect in weld seam；During welding, welding rod can make little crescent arc manipulation, to stop 0.5～1S in groove both sides, welding interlayer must thoroughly clear up welding slag, it has been found that when having the weld defects such as pore, arc crater must be filled up when weld defect being removed and received arc with portable emery wheel, in order to avoid producing crater crack；The joint of each interlayer should stagger, and must not have overlap；(3) SMAW cosmetic welding；Welding current is more slightly smaller than packed layer, should select correct welding rod angle, and arc manipulation is wanted uniformly, it is prevented that produce undercut defect in bevelled edge；Weld reinforcement to control at 1～3mm, it is to avoid welding point in use produces stress and concentrates.

6) when welding terminates, insulation material should be adopted immediately by weld seam and Jin Feng district covering and heat insulating, make joint Slow cooling, subsequently, then weldment entirety be heated to 720-760 DEG C, after constant temperature 1～2h, cool to room temperature with the furnace.

The preferred embodiment of the present invention described in detail above.Should be appreciated that those of ordinary skill in the art just can make many modifications and variations according to the design of the present invention without creative work.Therefore, all technical staff in the art, all should in the protection domain being defined in the patent claims under this invention's idea on the basis of existing technology by the available technical scheme of logical analysis, reasoning, or a limited experiment.

Claims (1)

1. a heat resisting pipe welding procedure, it is characterised in that comprise the steps, 1) method selection, adopt GTAW bottoming, the welding technique of manual electric arc welding filling and capping；2) select one side V-butt, mechanically process, should strictly control root gap and root face size, to guarantee the thorough penetration of backing weld seam；

3) each 20～30mm scope inside and outside the pipe of groove both sides should be polished totally before weldering, until exposing metallic luster, it is ensured that without oil stain, rust, moisture content, oxide or other harmful materials；Argon arc welding welding wire surface must not have the dirt such as oils and fats, rust；The welding rod of arc welding, must dry 1～2h through 350～400 DEG C before weldering, and deposit at 120 DEG C of heat-preservation cylinders, ready access upon use；Adopting 3～4 pieces of wedge type blocks to be Distribution and localization and be welded on groove, docking port must be concordant, and unfitness of butt joint cannot be greater than 0.5mm, and the wlding of tack welding and welding parameter are identical with formal welding, and positions weldering when preheating；

4) weld preheating: selecting preheating temperature is 200～300 DEG C, and preheated zone is centered by weld seam, and both sides are at least 100mm；In whole welding process, interlayer temperature should be kept to be not less than preheating temperature；

5) (1) bottom argon arc welding weldering；Being in by pipe fitting and horizontally rotate position welding, adopt short arc during welding, welding gun is vertical with surface of the work as far as possible, is conducive to the argon protection to welding pool；Welding gun and welding wire can slightly do teeter, it is ensured that groove both sides penetration；Meanwhile, bath temperature of controlling well prevents burn-through and welded tumour defects；At joint area, with portable grinder buffing arc crater, the weld defects such as the receipts burst check stricture of vagina at arc crater place and pore are removed, then proceed to striking welding；(2) SMAW fills weldering；Short arc should be adopted to weld, and heat input is unsuitable excessive；Weld according to long arc, not only there will be that arc burning instability, fusion penetration are shallow, fusing splatter is big and the problem such as alloying element scaling loss aggravation, and easily producing undercut, the defect such as lack of penetration, the harmful gas such as N2, O2 in air easily enters molten bath simultaneously, forms gas hole defect in weld seam；During welding, welding rod can make little crescent arc manipulation, to stop 0.5～1S in groove both sides, welding interlayer must thoroughly clear up welding slag, it has been found that when having the weld defects such as pore, arc crater must be filled up when weld defect being removed and received arc with portable emery wheel, in order to avoid producing crater crack；The joint of each interlayer should stagger, and must not have overlap；(3) SMAW cosmetic welding；Welding current is more slightly smaller than packed layer, should select correct welding rod angle, and arc manipulation is wanted uniformly, it is prevented that produce undercut defect in bevelled edge；Weld reinforcement to control at 1～3mm, it is to avoid welding point in use produces stress and concentrates；

6) when welding terminates, insulation material should be adopted immediately by weld seam and Jin Feng district covering and heat insulating, make joint Slow cooling, subsequently, then weldment entirety be heated to 720-760 DEG C, after constant temperature 1～2h, cool to room temperature with the furnace.