阅读说明：本技术 一种高强度钢丝的不预热焊接工艺 (Non-preheating welding process for high-strength steel wire ) 是由 陈冬英 于 2021-01-26 设计创作，主要内容包括：本发明公开了一种高强度钢丝的不预热焊接工艺,包括以下步骤：步骤一：准备碱性焊条,并严格烘干,放在保温箱中,随用随取,步骤二：第一道手工电弧焊,步骤三：正面焊接2～3道,使得焊缝与坡口壁圆滑过渡,步骤四：翻身,气刨清根,一段一段清理至无缺陷,然后不间断手工焊焊接4～6道,步骤五：不间断窄间隙埋弧自动焊,焊接完毕,步骤六：焊接完成后立即消氢处理,步骤七：石棉布包裹,缓慢冷却,采用双U形坡口,带微量直边,此时由于存在根部圆角半径,一般为5-8mm,有利于结晶裂纹,因为焊缝成型系数得到很大的改善,其焊缝稀释率比V形坡口小,而且焊后残余力较小,可以有效地防止产生冷裂纹,采用双U形坡,可以进行不预热焊接。(The invention discloses a non-preheating welding process of high-strength steel wires, which comprises the following steps: the method comprises the following steps: preparing an alkaline welding rod, strictly drying, putting the alkaline welding rod in a heat preservation box, and taking the alkaline welding rod at any time, wherein the second step is as follows: the first manual electric arc welding, step three: 2-3 welding on the front surface, so that the welding seam and the groove wall are in smooth transition, and the fourth step is: turning over, gouging back roots, cleaning one section to be free of defects, and then welding 4-6 times by uninterrupted manual welding, wherein the fifth step is that: uninterrupted narrow-gap submerged arc automatic welding, and after welding, the sixth step: and (5) after welding, immediately carrying out dehydrogenation treatment, and carrying out a seventh step: the asbestos cloth is wrapped and slowly cooled, a double-U-shaped groove is adopted, a trace straight edge is adopted, at the moment, the radius of a root fillet is generally 5-8mm, crystallization cracks are facilitated, the forming coefficient of a welding seam is greatly improved, the dilution rate of the welding seam is smaller than that of a V-shaped groove, the residual force after welding is small, cold cracks can be effectively prevented, and the double-U-shaped groove is adopted, so that welding can be carried out without preheating.)

1. A non-preheating welding process of high-strength steel wires is characterized by comprising the following steps:

the method comprises the following steps: preparing an alkaline welding rod, strictly drying the alkaline welding rod, putting the alkaline welding rod in a heat preservation box, and taking the alkaline welding rod at any time;

step two: carrying out first manual electric arc welding;

step three: 2-3 welding passes are performed on the front surface, so that the welding seam and the groove wall are in smooth transition;

step four: turning over, air gouging to remove roots, cleaning a section to be free of defects, and then continuously welding for 4-6 times by manual welding;

step five: uninterrupted narrow-gap submerged arc automatic welding is carried out, and the welding is finished;

step six: after welding, hydrogen is removed immediately;

step seven: wrapping with asbestos cloth, and slowly cooling.

2. The non-preheating welding process of high-strength steel wires according to claim 1, characterized in that: and in the first step, matched welding rods are selected, and before the argon arc welding rods are used, oil, dirt and the like on the surface are removed.

3. The non-preheating welding process of high-strength steel wires according to claim 1, characterized in that: and in the second step, a double U-shaped groove with a micro straight edge is formed before welding, and the root part has a fillet radius of 5-8 mm.

4. The non-preheating welding process of high-strength steel wires according to claim 1, characterized in that: in the fourth step, the groove is internally removed with rust, oil, scale and oxide skin until the metallic luster is exposed, and in order to prevent the oxidation of the root, it should be noted that in the carbon arc gouging process, the main function of the compressed air is to blow off the molten metal generated by the high-temperature heating of the carbon rod arc, and also to cool the carbon rod electrode, so as to correspondingly reduce the burning loss of the carbon rod, but when the flow of the compressed air is too large (greater than 0.6 mpa), the temperature of the molten metal is reduced, which is not beneficial to the processing of the metal to be cut.

5. The non-preheating welding process of high-strength steel wires according to claim 1, characterized in that: after the carbon arc air gouging of the low carbon steel in the fourth step, a hardened layer is generated on the surface of the gouging groove, which is formed by quenching high-temperature metal by compressed air and is not the result of carburization. Therefore, the welding of the low-carbon steel after the arc gouging can not influence the welding quality, when a high-power direct-current welding machine is used, a direct-current reverse connection method is needed to be adopted for gouging operation, namely a carbon rod is connected with an anode, a ground wire is connected with a cathode, and in the gouging process, the defects that air holes, slag inclusion and the like cannot exist in the welding line are observed.

6. The non-preheating welding process of high-strength steel wires according to claim 1, characterized in that: and in the fifth step, the processes of igniting the electric arc, feeding the wire, moving the electric arc along the welding direction, ending the welding and the like during submerged arc welding are completely completed by machinery.

7. The non-preheating welding process of high-strength steel wires according to claim 1, characterized in that: in the five submerged-arc welding steps, a layer of granular flux with the thickness of 30-50 mm is covered on a welding position of a workpiece, an electric arc is generated between the continuously fed welding wire and the workpiece under the flux layer, the welding wire, the workpiece and the flux are melted by the heat of the electric arc to form a metal molten pool, the metal molten pool and the metal molten pool are isolated from air, the metal, the welding wire and the flux of the workpiece in front are continuously melted by the electric arc along with the automatic forward movement of the welding machine, the edge behind the molten pool starts to be cooled and solidified to form a welding line, and liquid slag is then condensed to form a hard slag shell.

8. The non-preheating welding process of high-strength steel wires according to claim 1, characterized in that: the post-welding hydrogen elimination treatment in the sixth step is heat treatment performed after welding is completed and the welding seam is not cooled to be below 100 ℃, and the post-welding hydrogen elimination treatment mainly has the effect of accelerating hydrogen escape in the welding seam and a heat affected zone.

9. The non-preheating welding process of high-strength steel wires according to claim 1, characterized in that: in the sixth step, the post-welding dehydrogenation treatment temperature is heated to 200-350 ℃, and the temperature is kept for 2-6 hours.

10. The non-preheating welding process of high-strength steel wires according to claim 1, characterized in that: during the welding process, once the oxide color is found on the surface of the interlayer welding bead, the interlayer welding bead is ground by an angular grinding wheel so as to ensure that the welding seam has lower (0.5-0.8 mm) oxygen content.

Technical Field

The invention relates to the technical field of steel structure welding, in particular to a non-preheating welding process for high-strength steel wires.

Background

In summary, with the rapid development of power stations, petrochemical industries and atomic energy industries, the requirements for materials are also continuously increased, and equipment is required to stably work at high temperature and high pressure for a long time, so that various heat-resistant alloy steels are widely applied.

Heat-resistant alloy steels such as 10CrM, 910, 12Cr1MoV, 13CrMo44 and the like generally need to be preheated to 200 ℃ and 300 ℃ for welding, otherwise, welding cold cracks are easy to generate, and equipment damage can be caused. Welding preheating is beneficial to reducing the hardness of a welding seam and a heat affected zone, the diffusion and the escape of hydrogen are accelerated, and welding cold cracks can be effectively prevented; however, welding preheating has disadvantages, which increase the working hours of welders, consume more energy, and are harmful to the health of welders, even improper welding preheating can increase welding stress, resulting in thermal stress cracks, so that a new process method which can overcome the disadvantages of welding preheating and prevent welding cold cracks is urgently needed in production. In the process of manufacturing the first 30OMW boiler in 1971, a large number of welding cold cracks are found in dissimilar steel welding products of a reheater, and the repair loss is nearly millions of yuan. The analysis and treatment of the accident are inspired greatly, and whether a non-preheating welding process of the high-strength steel wire exists is a new problem worthy of research and discussion.

Disclosure of Invention

The invention aims to provide a non-preheating welding process of high-strength steel wires, which aims to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: a non-preheating welding process of high-strength steel wires comprises the following steps:

the method comprises the following steps: preparing an alkaline welding rod, strictly drying the alkaline welding rod, putting the alkaline welding rod in a heat preservation box, and taking the alkaline welding rod at any time;

step two: carrying out first manual electric arc welding;

step three: 2-3 welding passes are performed on the front surface, so that the welding seam and the groove wall are in smooth transition;

step four: turning over, air gouging to remove roots, cleaning a section to be free of defects, and then continuously welding for 4-6 times by manual welding;

step five: uninterrupted narrow-gap submerged arc automatic welding is carried out, and the welding is finished;

step six: after welding, hydrogen is removed immediately;

step seven: wrapping with asbestos cloth, and slowly cooling.

Preferably, a matched welding rod is selected in the first step, and oil, dirt and the like on the surface are removed before the argon arc welding rod is used.

Preferably, in the second step, a double-U-shaped groove with a slight straight edge is formed before welding, and the root part has a fillet radius of 5-8 mm.

Preferably, in the fourth step, the groove is internally provided with rust, oil, scale and oxide skin which are removed until the metallic luster is exposed, and in order to prevent the oxidation of the root, it should be noted that in the carbon arc gouging process, the main function of the compressed air is to blow off the molten metal generated by the high-temperature heating of the carbon rod arc, and also to cool the carbon rod electrode, so that the burning loss of the carbon rod can be correspondingly reduced, but when the flow of the compressed air is too large, the temperature of the molten metal is reduced, and the processing of the metal to be cut is not facilitated.

Preferably, after carbon arc air gouging of the low carbon steel in the fourth step, a hardened layer is formed on the surface of the gouging groove, which is formed by quenching the high temperature metal by the compressed air and is not a result of carburization. Therefore, the welding of the low-carbon steel after the arc gouging can not influence the welding quality, when a high-power direct-current welding machine is used, a direct-current reverse connection method is needed to be adopted for gouging operation, namely a carbon rod is connected with an anode, a ground wire is connected with a cathode, and in the gouging process, the defects that air holes, slag inclusion and the like cannot exist in the welding line are observed.

Preferably, in the step five, the processes of igniting the electric arc, feeding the wire, moving the electric arc along the welding direction, ending the welding and the like during submerged arc welding are completely completed by a machine.

Preferably, in the step five submerged arc welding, the welding position of the workpiece is covered with a granular flux with the thickness of 30-50 mm, the continuously fed welding wire generates an electric arc between the lower part of the flux layer and the workpiece, the heat of the electric arc melts the welding wire, the workpiece and the flux to form a molten metal pool, the molten metal pool and the molten metal pool are isolated from air, the electric arc continuously melts the metal, the welding wire and the flux of the workpiece in front as the welding machine automatically moves forwards, the edge behind the molten pool starts to cool and solidify to form a welding line, and the liquid slag is subsequently condensed to form a hard slag shell.

Preferably, the post-welding dehydrogenation treatment in the sixth step refers to low-temperature heat treatment performed after the welding is completed and the welding seam is not cooled to be below 100 ℃, and the main function of the post-welding dehydrogenation treatment is to accelerate the escape of hydrogen in the welding seam and a heat affected zone.

Preferably, in the sixth step, the post-welding dehydrogenation treatment temperature is 200-350 ℃ by heating, and the temperature is kept for 2-6 hours.

Preferably, once oxidation color is found on the surface of the interlayer weld bead during welding, the interlayer weld bead is ground by an angular grinding wheel so as to ensure that the oxygen content of the weld joint is low.

Compared with the prior art, the invention has the beneficial effects that:

1. the non-preheating welding process of the high-strength steel wire adopts the double-U-shaped groove with the trace straight edges, and is beneficial to crystal cracks because of the existence of root fillet radius which is generally 5-8mm at the moment.

2. The non-preheating welding process of the high-strength steel wire adopts the technical measures of double U-shaped grooves, manual welding bottoming, hydrogen elimination after welding and the like, and can carry out non-preheating welding.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a technical scheme that: a non-preheating welding process of high-strength steel wires comprises the following steps:

the method comprises the following steps: preparing an alkaline welding rod, strictly drying the alkaline welding rod, putting the alkaline welding rod in a heat preservation box, and taking the alkaline welding rod at any time;

step two: carrying out first manual electric arc welding;

step three: 2-3 welding passes are performed on the front surface, so that the welding seam and the groove wall are in smooth transition;

step four: turning over, air gouging to remove roots, cleaning a section to be free of defects, and then continuously welding for 4-6 times by manual welding;

step five: uninterrupted narrow-gap submerged arc automatic welding is carried out, and the welding is finished;

step six: after welding, hydrogen is removed immediately;

step seven: wrapping with asbestos cloth, and slowly cooling.

Furthermore, in the first step, matched welding rods are selected, and oil, dirt and the like on the surface are removed before the argon arc welding rods are used.

Further, in the second step, a double U-shaped groove with a trace straight edge is formed before welding, the root part has a fillet radius of 5-8mm, the double U-shaped groove is adopted, the trace straight edge is formed, the fillet radius of the root part is generally 5-8mm at the moment, crystallization cracks are facilitated, the weld forming coefficient is greatly improved, the weld dilution rate is smaller than that of the V-shaped groove, the residual force after welding is smaller, cold cracks can be effectively prevented from being generated, the double U-shaped groove, manual welding backing, hydrogen elimination after welding and other technological measures can be adopted, non-preheating welding can be carried out, double U-shaped grooves with a trace straight edge are adopted, the fillet radius of the root part is generally 5-8mm at the moment, crystallization cracks are facilitated, and the weld forming coefficient is greatly improved, the weld dilution rate is smaller than that of the V-shaped groove, and the residual force after welding is smaller, so that cold cracks can be effectively prevented.

Furthermore, in the fourth step, the groove is internally removed with rust, oil, scale and oxide skin until the metallic luster is exposed, and in order to prevent the oxidation of the root, it should be noted that in the carbon arc gouging process, the main function of the compressed air is to blow off the molten metal generated by the high-temperature heating of the carbon rod arc, and also to cool the carbon rod electrode, so as to correspondingly reduce the burning loss of the carbon rod, but when the flow of the compressed air is too large, the temperature of the molten metal is reduced, and the metal to be cut is not easy to process.

Further, after the carbon arc air gouging of the low carbon steel in the fourth step, a hardened layer is generated on the surface of the gouging groove, which is formed by quenching the high temperature metal by the compressed air and is not the result of carburizing. Therefore, the welding of the low-carbon steel after the arc gouging can not influence the welding quality, when a high-power direct-current welding machine is used, a direct-current reverse connection method is needed to be adopted for gouging operation, namely a carbon rod is connected with an anode, a ground wire is connected with a cathode, and in the gouging process, the defects that air holes, slag inclusion and the like cannot exist in the welding line are observed.

Furthermore, in the fifth step, the processes of igniting the electric arc, feeding the wire, moving the electric arc along the welding direction, ending the welding and the like during submerged arc welding are completely completed by a machine.

Further, in the fifth step of submerged arc welding, the welded part of the workpiece is covered with a granular flux with the thickness of 30-50 mm, the continuously fed welding wire generates an electric arc between the lower part of the flux layer and the workpiece, the heat of the electric arc melts the welding wire, the workpiece and the flux to form a molten metal pool, the molten metal pool and the molten metal pool are isolated from air, the electric arc continuously melts the metal, the welding wire and the flux of the workpiece in front along with the automatic forward movement of the welding machine, the edge behind the molten pool starts to cool and solidify to form a welding line, and the liquid slag is subsequently condensed to form a hard slag shell.

Further, the post-welding dehydrogenation treatment in the sixth step refers to low-temperature heat treatment performed after welding is completed and the welding seam is not cooled to be below 100 ℃, and the main effect of the post-welding dehydrogenation treatment is to accelerate hydrogen escape from the welding seam and a heat affected zone.

Further, in the sixth step, the post-welding dehydrogenation treatment temperature is heated to 200-350 ℃, and the temperature is kept for 2-6 hours.

Furthermore, in the welding process, once the oxide color is found on the surface of the interlayer welding bead, angular grinding is adopted for grinding so as to ensure the lower oxygen content of the welding line. .

The working principle is as follows: the method comprises the following steps: preparing an alkaline welding rod, strictly drying the alkaline welding rod, putting the alkaline welding rod in a heat preservation box, taking the alkaline welding rod at any time, namely selecting a matched welding rod, removing oil and scale on the surface before the argon arc welding rod is used, and the like, wherein the second step is as follows: in the first manual electric arc welding, a double U-shaped groove with a trace straight edge is formed before welding, and the root part has a fillet radius of 5-8mm at the moment, and the third step is that: 2-3 welding on the front surface, so that the welding seam and the groove wall are in smooth transition, and the fourth step is: turning over, gouging back roots, cleaning one section to be free of defects, and then welding 4-6 times by uninterrupted manual welding, wherein the fifth step is that: uninterrupted narrow-gap submerged arc automatic welding, and after welding, the sixth step: and (5) after welding, immediately carrying out dehydrogenation treatment, and carrying out a seventh step: wrapping with asbestos cloth, and slowly cooling.

In conclusion, the non-preheating welding process of the high-strength steel wire adopts the double-U-shaped groove with a trace of straight edges, is beneficial to crystal cracks because of the root fillet radius which is generally 5-8mm, has a smaller dilution rate than the V-shaped groove because the forming coefficient of the welding seam is greatly improved, has smaller residual force after welding, can effectively prevent cold cracks, and can carry out non-preheating welding by adopting the technical measures of double-U-shaped groove, manual welding bottoming, hydrogen elimination after welding and the like.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.