阅读说明：本技术 一种长途运输螺旋钢管防裂除锈加工工艺 (Crack-resistant rust-removing processing technology for long-distance transportation spiral steel pipe ) 是由 边林昌 于 2019-03-20 设计创作，主要内容包括：本发明公开了一种长途运输螺旋钢管防裂除锈加工工艺,属于钢管制备技术领域,其技术方案要点是包括钢带拆卷-辊式矫平-钢带除锈-切头、钢带对头焊接-滚套成型、内焊、外焊-定尺切割-焊剂处理,除锈包括以下步骤：一次除锈；制备二次除锈时的除锈剂,按重量份数计,第一步将柠檬酸15-21份、钼酸钠0.8-5.2份、磷酸0.8-1.4份、水50-70份加入混合罐内,搅拌30min；第二步在混合液中加入碘化钾0.01-0.1份,搅拌30分钟；二次除锈；油污处理,油污处理剂包括十二烷基苯磺酸钠10-20份、辛基酚聚氧乙烯醚12-16份、磷酸10-14份、木质素磺酸钠5-9份；将油污处理后的钢带用清水进行清洗,再进行下一个工序。达到减少螺旋钢管焊缝处的气孔量的效果。(The invention discloses an anti-cracking and rust-removing processing technology for a long-distance transport spiral steel pipe, which belongs to the technical field of steel pipe preparation, and adopts the technical scheme that the processing technology comprises steel belt uncoiling, roller type leveling, steel belt rust removing, head cutting, steel belt butt welding, roller sleeve forming, inner welding, outer welding, fixed length cutting and flux treatment, and the rust removing comprises the following steps: primary rust removal; preparing a rust remover for secondary rust removal, adding 15-21 parts of citric acid, 0.8-5.2 parts of sodium molybdate, 0.8-1.4 parts of phosphoric acid and 50-70 parts of water into a mixing tank in parts by weight, and stirring for 30 min; secondly, adding 0.01-0.1 part of potassium iodide into the mixed solution, and stirring for 30 minutes; secondary rust removal; oil stain treatment, wherein the oil stain treatment agent comprises 10-20 parts of sodium dodecyl benzene sulfonate, 12-16 parts of octylphenol polyoxyethylene ether, 10-14 parts of phosphoric acid and 5-9 parts of sodium lignosulphonate; and cleaning the steel strip subjected to the oil stain treatment by using clean water, and then performing the next procedure. The effect of reducing the amount of air holes at the welding seam of the spiral steel pipe is achieved.)

1. A long-distance transport spiral steel pipe crack control and rust removal processing technology comprises steel belt uncoiling, roller type leveling, steel belt rust removal, head cutting, steel belt end-to-end welding, roller sleeve forming, inner welding, outer welding, fixed length cutting and welding flux treatment, and is characterized in that the rust removal comprises the following steps:

s1: carrying out primary rust removal, namely conveying the leveled steel strip to a shot blasting machine for shot blasting treatment to enable rust on the surface of the steel strip to fall off, wherein the included angle between a high-pressure nozzle of the shot blasting machine and the surface of the steel strip is 30-60 degrees;

s2: preparing a rust remover for secondary rust removal, adding 15-21 parts of citric acid, 0.8-5.2 parts of sodium molybdate, 0.8-1.4 parts of phosphoric acid and 50-70 parts of water into a mixing tank at room temperature in parts by weight, and stirring for 30 min; secondly, adding 0.01-0.1 part of potassium iodide into the mixed solution, and stirring for 30 minutes;

s3: carrying out secondary rust removal, namely carrying out surface oil stain treatment on the steel strip subjected to primary rust removal by using a rust remover, conveying the steel strip subjected to primary rust removal into a hot washing container, controlling the temperature to be between 80 and 95 ℃, spraying the rust remover by using a high-pressure spray head, and carrying out secondary cleaning on rust spots subjected to primary rust removal;

s4: performing oil stain treatment, namely performing oil stain treatment on the steel strip subjected to secondary rust removal, wherein the oil stain treatment agent comprises 10-20 parts by weight of sodium dodecyl benzene sulfonate, 12-16 parts by weight of octylphenol polyoxyethylene ether, 10-14 parts by weight of phosphoric acid and 5-9 parts by weight of sodium lignosulfonate;

s5: and cleaning the steel strip subjected to the oil stain treatment by using clean water, and then performing the next procedure.

2. The anti-cracking and rust-removing processing technology for the long-distance transport spiral steel pipe as claimed in claim 1, is characterized in that: in S1, an included angle between a high-pressure nozzle of the shot blasting machine and the surface of the steel strip is 45 degrees.

3. The anti-cracking and rust-removing processing technology for the long-distance transport spiral steel pipe as claimed in claim 1, is characterized in that: in S2, 18 parts of citric acid, 3 parts of sodium molybdate, 1.1 parts of phosphoric acid, 60 parts of water and 0.06 part of potassium iodide.

4. The anti-cracking and rust-removing processing technology for the long-distance transport spiral steel pipe as claimed in claim 1, is characterized in that: in S2, 5-11 parts of glycerol are added in the second step.

5. The anti-cracking and rust-removing processing technology for the long-distance transport spiral steel pipe as claimed in claim 4, wherein the processing technology comprises the following steps: in S2, 8 parts of glycerin are added in the second step.

6. The anti-cracking and rust-removing processing technology for the long-distance transport spiral steel pipe as claimed in claim 1, is characterized in that: in S4, the oil stain treating agent comprises 15 parts of sodium dodecyl benzene sulfonate, 14 parts of octylphenol polyoxyethylene ether, 12 parts of phosphoric acid and 7 parts of sodium lignosulphonate.

7. The anti-cracking and rust-removing processing technology for the long-distance transport spiral steel pipe as claimed in claim 1, is characterized in that: in S4, the oil stain treating agent also comprises NH in parts by weight₄Cl2.8-6.8 parts.

8. The anti-cracking and rust-removing processing technology for the long-distance transport spiral steel pipe as claimed in claim 7, is characterized in that: the oil stain treating agent also comprises NH in parts by weight₄Cl 5。

Technical Field

The invention relates to the technical field of steel pipe preparation, in particular to an anti-cracking and rust-removing processing technology for a long-distance transportation spiral steel pipe.

Background

In recent years, as development and exploitation of natural gas extend to remote areas such as deserts, polar regions, oceans and the like, long-distance pipelines not only pass through geology such as frozen soil zones, landslide zones, earthquake zones and the like, but also undergo deformation of steel pipes caused by ground collapse and movement, and may undergo enormous deformation and stress. Therefore, from the viewpoint of technical progress and pipeline safety, new and higher requirements are put forward on welded pipes and pipe fittings to ensure the safety and integrity of pipelines.

The spiral steel pipe is widely applied to industrial conveying pipelines, mechanical structural parts and the like in petroleum, chemical engineering, medical treatment, food, light industry, mechanical instruments and the like. The spiral steel pipe is made by rolling a low-carbon structural steel or low-alloy structural steel strip into a pipe blank according to a certain spiral angle and then welding the pipe seam. Before welding the spiral steel pipe, firstly uncoiling coiled steel strips, carrying out roller leveling, derusting, cutting ends, carrying out end-to-end welding on the steel strips, carrying out roller sleeve forming, carrying out internal welding and external welding, cutting to length, and carrying out flux treatment. However, the quality of the weld joint of the spiral steel pipe is a main factor influencing the service life of the spiral steel pipe, after the existing spiral steel pipe is welded, the weld joint of the pipeline has local metal fracture and pores in the weld joint, the steel belt is not cleaned cleanly in the rust removal process, the probability of the pores is improved, the local metal fracture and the pores in the weld joint influence the bearing capacity of the pipeline in the use process, and therefore the service life of the steel pipe is also shortened.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide an anti-cracking and rust-removing processing technology for a long-distance transportation spiral steel pipe, and the effect of reducing the amount of air holes at the welding seam of the spiral steel pipe is achieved.

The technical purpose of the invention is realized by the following technical scheme:

a long-distance transport spiral steel pipe crack-resistant and rust-removing processing technology comprises steel belt uncoiling, roller type leveling, steel belt rust-removing, head cutting, steel belt end-to-end welding, rolling sleeve forming, inner welding, outer welding, fixed length cutting and welding flux treatment, wherein the rust-removing process comprises the following steps:

s1: carrying out primary rust removal, namely conveying the leveled steel strip to a shot blasting machine for shot blasting treatment to enable rust on the surface of the steel strip to fall off, wherein the included angle between a high-pressure nozzle of the shot blasting machine and the surface of the steel strip is 30-60 degrees;

s2: preparing a rust remover for secondary rust removal, adding 15-21 parts of citric acid, 0.8-5.2 parts of sodium molybdate, 0.8-1.4 parts of phosphoric acid and 50-70 parts of water into a mixing tank at room temperature in parts by weight, and stirring for 30 min; secondly, adding 0.01-0.1 part of potassium iodide into the mixed solution, and stirring for 30 minutes;

s3: carrying out secondary rust removal, namely carrying out surface oil stain treatment on the steel strip subjected to primary rust removal by using a rust remover, conveying the steel strip subjected to primary rust removal into a hot washing container, controlling the temperature to be between 80 and 95 ℃, spraying the rust remover by using a high-pressure spray head, and carrying out secondary cleaning on rust spots subjected to primary rust removal;

s4: performing oil stain treatment, namely performing oil stain treatment on the steel strip subjected to secondary rust removal, wherein the oil stain treatment agent comprises 10-20 parts by weight of sodium dodecyl benzene sulfonate, 12-16 parts by weight of octylphenol polyoxyethylene ether, 10-14 parts by weight of phosphoric acid and 5-9 parts by weight of sodium lignosulfonate;

s5: and cleaning the steel strip subjected to the oil stain treatment by using clean water, and then performing the next procedure.

Through adopting above-mentioned technical scheme, the existence of iron rust and moisture on the steel band, the double-layered pearl type gas pocket can appear, when the iron rust on steel band surface can not get rid of completely, the steel band warp the deformation back through the shaper, some adnexed, that clear away unclean iron rust drop, participate in the internal welding process with interior welding agent being in the same place, under the high temperature effect, the oxidation has been strengthened to the molten bath to rust release department hydrogen and oxygen, impels to generate the CO gas pocket when the crystallization, lead to spiral steel pipe's the also corresponding reduction of holding capacity.

When the rust removal is carried out on the steel strip through sand blasting firstly, the rust which is not firmly adhered to the steel strip can be removed, most of the rust on the surface of the steel strip can be removed in the sand blasting process, meanwhile, the surface of the steel strip can present certain roughness in the contact process of the sand blasting and the surface of the steel strip, the roughness on the surface of the steel strip is beneficial to reducing the resistance between fluid and the inner wall of the spiral steel tube in the use process of the spiral steel tube, so that the bearing capacity of the surface of the spiral steel tube is correspondingly reduced, the service life of the spiral steel tube is prolonged, when the clamping between a high-pressure nozzle and the surface of the steel strip is 30-60 degrees during sand blasting, the force of the sand blasting on the steel strip can be reduced, and the influence.

After sand blasting for rust removal, rust spots on the surface of the steel strip cannot be completely removed, so secondary rust removal is needed. The citric acid and the phosphoric acid in the rust remover belong to weak acids, so that the rust on the surface of the steel strip can be removed, meanwhile, the corrosion to the surface of the steel strip is reduced, the phosphoric acid and the sodium molybdate are mixed for use, a certain corrosion inhibition effect is achieved, the acidic substances are prevented from continuously reacting with the steel strip to influence the service life of the steel strip, and the corrosion inhibition effect of the sodium molybdate and the phosphoric acid can be enhanced by adding the potassium iodide. The citric acid, the sodium molybdate, the phosphoric acid and the potassium iodide are used in a matching way, so that the rust on the surface of the steel strip can be further removed effectively, and the influence of the rust on welding is reduced.

In the process of derusting the steel strip, some greasy dirt on the surface of the steel strip can not be completely removed, and the existence of the greasy dirt can reduce the welding performance of the steel strip, so that after the derusting agent derusts the steel strip, the independent greasy dirt on the steel strip is removed, and after the greasy dirt and the rust are removed, the corrosion of acidic substances to the steel strip in the derusting process can be reduced, meanwhile, the greasy dirt on the surface of the steel strip can be quickly removed, the later manual operation is not needed, and the processing efficiency of the spiral steel tube is improved.

The sodium dodecyl benzene sulfonate, the octyl phenol polyoxyethylene ether and the sodium lignin sulfonate can be dissolved in water, the sodium dodecyl benzene sulfonate is strong in foaming capacity and high in decontamination capacity, can be effectively combined with oily substances on the surface of a steel strip, and meanwhile, the sodium dodecyl benzene sulfonate has good surface activity and strong hydrophilicity and effectively reduces the tension of an oil-water interface, so that the contact area of the sodium dodecyl benzene sulfonate and oil stains is increased, and the decontamination capacity is improved; because the sodium dodecyl benzene sulfonate is sensitive to water hardness, the combination of the sodium dodecyl benzene sulfonate, the polyoxyethylene octylphenol ether and the sodium lignosulfonate can improve the dirt-removing capability of the sodium dodecyl benzene sulfonate and also contribute to the degradation of the polyoxyethylene octylphenol ether.

The invention is further arranged in that in S1, the included angle between the high-pressure spray head of the shot blasting machine and the surface of the steel strip is 45 degrees.

By adopting the technical scheme, when the included angle between the high-pressure spray nozzle and the surface of the steel strip is 45 degrees, the damage to the surface of the steel strip is reduced, and the rust on the surface of the steel strip can be removed, so that the roughness of the surface of the steel strip is kept consistent, and the influence on welding is reduced.

The invention is further provided that in S2, 18 parts of citric acid, 3 parts of sodium molybdate, 1.1 parts of phosphoric acid, 60 parts of water and 0.06 part of potassium iodide are added.

The invention is further configured such that, in S2, 5 to 11 parts of glycerol are added in the second step.

Through adopting above-mentioned technical scheme, glycerine is odorless, use the environmental protection, can not exert an influence to the human body, glycerine is as the solvent of citric acid, sodium molybdate, phosphoric acid and potassium iodide simultaneously, can make citric acid, sodium molybdate, phosphoric acid and potassium iodide effectively dissolve in aqueous, because glycerine has certain consistency, can improve the adhesion time of citric acid, sodium molybdate, phosphoric acid and potassium iodide and steel band in adding the rust remover with glycerine, thereby help improving the derusting effect of rust remover, also reduce the waste of rust remover simultaneously.

The invention is further configured such that, in S2, 8 parts of glycerol are added in the second step.

By adopting the technical scheme, the amount of glycerin is too small, the adhesion performance is correspondingly lower, but when the amount of glycerin is more, the consistency of the rust remover is increased, the adhesion time of the corresponding rust remover on a steel strip is increased, and the corrosion of acidic substances to the steel strip is accelerated, so that when the amount of glycerin is 6 parts, the corrosion of the acidic substances to the steel strip can be reduced, and the rust removing capability is also effectively improved.

The invention is further set that in S4, the oil stain treating agent comprises 15 parts of sodium dodecyl benzene sulfonate, 14 parts of octyl phenol polyoxyethylene ether, 12 parts of phosphoric acid and 7 parts of sodium lignosulphonate.

The invention is further provided that in S4, the oil stain treatment agent also comprises NH in parts by weight₄Cl2.8-6.8 parts.

The invention is further provided that the oil stain treatment agent also comprises NH in parts by weight₄Cl 5。

By adopting the technical scheme, NH₄Aqueous Cl solution is weakly acidic, NH₄When Cl is added into the oil stain treatment agent, further treatment can be carried out on rusty spots on the surface of the steel strip, meanwhile, ammonium ions can not react with iron, meanwhile, corrosion to the steel strip and NH can not be caused₄The existence of Cl can increase the viscosity of the mixed solution of sodium dodecyl benzene sulfonate, octyl phenol polyoxyethylene ether, phosphoric acid and sodium lignosulfonate, increase the adhesive force of the oil stain treating agent and a steel belt, and effectively improve the decontamination of the oil stain treating agentCapability.

In conclusion, the invention has the following beneficial effects:

1. the addition of citric acid, phosphoric acid, sodium molybdate and potassium iodide can reduce corrosion to the steel pipe and remove oxides on the surface of the steel pipe, and the addition of potassium iodide can enhance the corrosion inhibition effect of sodium molybdate and phosphoric acid, prolong the service life of the steel pipe and improve the welding performance;

2. glycerol and NH₄The addition of Cl can improve the binding force between the oil stain treatment agent and the steel pipe, improve the oil stain treatment efficiency, remove the residual oxides on the surface of the steel pipe, indirectly improve the welding performance of the steel pipe, reduce air holes and cracks in a welding line during welding and enable the spiral steel pipe to be suitable for length transportation.

Detailed Description