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Method for producing martensitic stainless steel seamless steel pipe

A martensitic stainless steel, seamless steel pipe technology, used in forming tools, rolling mill control devices, metal rolling, etc., can solve the problems of poor surface quality, difficult processing, rough surface, etc., and achieve small tolerances on outer diameter and wall thickness , to prevent uneven deformation, the effect of good surface quality

Inactive Publication Date: 2009-03-04
JIANGSU HONGBAO GROUP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, because the yield strength of this type of material is relatively high, it is difficult to process it. In the existing production methods of martensitic stainless steel seamless steel pipes, in the processes of piercing and rolling, hot piercing combined with hot rolling or Continuous casting and rolling, such as the methods disclosed in Chinese patents CN96116963.X, CN90109547.8, CN200510059854.8, CN200610038586.6, and these methods focus on the adjustment of trace elements in the material or quenching-tempering, etc. However, these existing production processes still have defects: the outer diameter and wall thickness tolerance of the steel pipe after processing is relatively large, and the surface quality is poor, usually manifested as rough surface, unevenness and cracks, etc.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The piercing step of the present invention is a continuous, equal-diameter hot piercing process, and the plug in the hot piercing process is a non-wearing plug, and immediately enters the cold rolling step after the hot piercing, and the cold rolling step adopts a large deformation Amount, single pass is 1.4 ~ 1.6mm, at the same time requires the amount of wall reduction of waste tube: the amount of diameter reduction is greater than 1:3.

[0028] The inventor used a 90×7.5mm waste pipe to roll it into a 73×6mm seamless steel pipe, and the sample size was 5 pieces. The specific data are shown in the table below: Unit: mm

[0029] serial number Size before rolling Rolled products Outer diameter size (four points) Wall thickness tolerance (four points) 1 90×7.5 73×6 73.32，73.1，72.7，72.9 6.25，6.35，6.28，6.05 2 90×7.5 73×6 73.28，73.14，72.7，72.85 6.4，6.31，6.11，5.68 3 90×7.5 73×6 73.35，73.2，73.01，72.9 6.3，6.02，5.92，5.73 4 90×7.5 73...

Embodiment 2

[0031] The main difference between this embodiment and the above embodiments lies in the pickling step in the production process of seamless steel pipes. In the production method of the present invention, the pickling solution used in the pickling step is 20-30% sulfuric acid solution, and , 0.5-5% NaCl and 1-10% NaNO are also added to the pickling solution 3 As a sustained release agent, in addition, in the pickling step, the pickling solution is heated to a temperature of 50-80°C. This cleans the scale surface and leaves it smooth without over-pickling.

Embodiment approach

[0032] For this specific implementation, the applicant of the present invention has also carried out multiple tests and obtained the following data to prove the beneficial effect of the present invention.

[0033] Pickling record of L8013Cr

[0034] time Steel pipe size mm Solution composition temperature °C time Effect

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PUM

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Abstract

The invention relates to a method for producing a martensitic stainless steel seamless steel pipe, which comprises the steps of heating, piercing, rolling, acid cleaning and straightening a pipe blank, wherein the step of the piercing is a continuous and equal-diameter hot piercing process, and the step of the rolling is the cold rolling. The invention adopts the continuous and equal-diameter hot piercing process, and adopts a cold rolling process in the rolling process, thereby effectively preventing tube materials from being unevenly deformed; and the produced steel pipe has the advantages of small tolerance between the outer diameter and the wall thickness, high accuracy, and better quality and more smooth surface. In addition, the invention further adopts a mild straightening process in the step of straightening. Therefore, the seamless steel pipe has little possibility in crack rectification and the produced steel pipe has fine straightness and degree of curve being less than 1.5mm / m.

Description

Technical field: [0001] The present invention relates to a production method of a seamless steel pipe, more specifically, to a production method of a martensitic stainless steel seamless steel pipe. Background technique: [0002] Martensitic stainless steel such as 1Cr13 and 1Cr12Mo has the advantages of good corrosion resistance, high toughness and good cold deformation performance, and it has good vibration damping properties, and is widely used in steam turbines, stationary blades, and compressors. Guide vanes and other corrosion-resistant parts, such as generator water tanks, water tank rings, center pipes, water joint flanges, etc., can also be used in important fields such as the nuclear industry. According to its thermal strength, it can be used below 450 °C. However, because the yield strength of this type of material is relatively high, it is difficult to process it. In the existing production methods of martensitic stainless steel seamless steel pipes, in the proce...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B21B19/04B21B19/06B21B37/78C23G1/02C23G1/04B21B15/00B21D3/00B21D37/16
Inventor 王忠华
Owner JIANGSU HONGBAO GROUP CO LTD
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