Two-pass continuous drawing method for producing cold-drawn steel pipe

A cold-drawn steel pipe and secondary cooling technology, which is used in the field of two-pass continuous drawing to produce cold-drawn steel pipes, can solve the problem of errors in the setting value of wall thickness reduction, small reduction in outer diameter and wall thickness, and influence on product qualification rate, etc. problems, to achieve the effect of reducing uneven wall thickness, reducing heat treatment costs, and reducing the probability of defects

Inactive Publication Date: 2016-08-10
CHONGQING IRON & STEEL (GRP) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] This multi-pass cold drawing process has three major defects: First, because each pass in the multi-pass cold drawing process reduces the outer diameter and wall thickness of the pipe material, the continuous drawing rate is also very low, resulting in The production cycle of the product is long, which seriously limits the output
The second is that the actual outer diameter and wall thickness reduction value of each pass of cold drawing will have an error with the set value. The more passes, the greater the cumulative effect of the error, which will also affect the pass rate of the product.
The third is that due to the lack of extensibility of the waste pipe, defec

Method used

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  • Two-pass continuous drawing method for producing cold-drawn steel pipe
  • Two-pass continuous drawing method for producing cold-drawn steel pipe
  • Two-pass continuous drawing method for producing cold-drawn steel pipe

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0061] Example 1

[0062] Taking steel grade 20G and Ф76×5.3mm tube blanks as raw materials, the above-mentioned method is used to produce 10 cold-drawn steel pipes with steel grade 20G and finished product specifications Ф51×5mm on the same square:

[0063] 1) Pretreatment: Drilling and heading the tube blank to obtain a pretreated waste tube;

[0064] 2) Pickling: Put the pretreated waste pipe obtained in step 1) into the pickling tank for pickling until there is no iron oxide scale on the pretreated waste pipe; then wash it with clean water 2 to 3 times to remove the remaining pickling liquid , Get pickling waste pipe. The pickling solution is a sulfuric acid solution with a mass fraction of 17-20% and a temperature of 45-60°C. Corrosion inhibitors are added to prevent excessive pickling.

[0065] 3) Phosphating: Put the above-mentioned acid-washed waste pipe in a phosphating tank for phosphating for 20 to 35 minutes to form a phosphate film on the surface, and then wash it with w...

Example Embodiment

[0079] Example 2

[0080] Using the steel grade 20G, Ф76×6.3mm tube billet as raw material, the above method is used to produce 10 cold drawn steel pipes of 20G steel grade and the finished product size Ф51×6mm on a straight line:

[0081] 1) Pretreatment: Drilling and heading the tube blank to obtain a pretreated waste tube;

[0082] 2) Pickling: Put the pretreated waste pipe obtained in step 1) into the pickling tank for pickling until there is no iron oxide scale on the pretreated waste pipe; then wash it with clean water 2 to 3 times to remove the remaining pickling liquid , Get pickling waste pipe. The pickling solution is a sulfuric acid solution with a mass fraction of 17-20% and a temperature of 45-60°C. Corrosion inhibitors are added to prevent excessive pickling.

[0083] 3) Phosphating: Put the above-mentioned acid-washed waste pipe in a phosphating tank for phosphating for 20 to 35 minutes to form a phosphate film on the surface, and then wash it with water for 2 to 3 tim...

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Abstract

The invention discloses a two-pass continuous drawing method for producing a cold-drawn steel pipe. The method comprises the steps of pretreatment, pickling, phosphating, lubrication, cold drawing of rod with mandrel, drawing, and heat treatment. By changing the interaction of pickling, phosphating and lubrication, the physical and chemical properties of the pierced billet are improved greatly, especially the extension and isotropy are greatly improved greatly. Finally, the time and temperature of the heat treatment are controlled to eliminate internal stress of the product. The above processes as an organic continuous production process are indispensable to ensure parameters of each part and to obtain product with good mechanical properties and certain antirust ability, thereby reducing the pass frequency of cold drawing and reducing production cost.

Description

technical field [0001] The invention belongs to the technical field of metal material forming, and in particular relates to a method for producing cold-drawn steel pipes by two-pass continuous drawing. Background technique [0002] As a fluid conveying material, cold-drawn steel pipes have been widely used in production, such as high-pressure boiler pipes, petroleum cracking pipes, high-pressure fertilizer pipes, low and medium pressure boiler pipes, etc. At present, the method of producing cold-drawn steel pipes is to use large-diameter pipe materials as raw materials, undergo pretreatments such as pickling and phosphating, and then draw through multiple passes (at least three passes) to obtain the design. Cold-drawn steel pipes of fixed diameter. [0003] This multi-pass cold drawing process has three major defects: First, because each pass in the multi-pass cold drawing process reduces the outer diameter and wall thickness of the pipe material, the continuous drawing rat...

Claims

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Application Information

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IPC IPC(8): B21C1/24B21C9/00C23G1/04C25D11/36
CPCB21C1/24B21C9/00C23G1/04C25D11/36
Inventor 李键君赵文涛胡婷樊胜洪鲁文庆
Owner CHONGQING IRON & STEEL (GRP) CO LTD
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