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Method for production of martensitic stainless steel pipe

A technology of stainless steel pipes and manufacturing methods, applied in the direction of manufacturing tools, metal rolling, furnace types, etc., which can solve undisclosed problems and achieve the effect of suppressing flashing

Inactive Publication Date: 2010-11-03
NIPPON STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The invention in the above-mentioned Patent Document 1 increases the manufacturing cost due to the need to add forced cooling equipment
[0007] As mentioned above, the prevention of cracks when cutting martensitic stainless steel pipes has been studied in the past, but the technology for suppressing the generation of burrs has not been disclosed.

Method used

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  • Method for production of martensitic stainless steel pipe
  • Method for production of martensitic stainless steel pipe

Examples

Experimental program
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Effect test

Embodiment

[0041] Steel slabs having the chemical composition shown in Table 1 were smelted and hot-processed with a Mannesmann mandrel mill to produce seamless tubes with various outer diameters (that is, various degrees of outer diameter processing) and a length of 10 m. Seam steel pipe. The tube was heated for an additional 16 minutes in a furnace at a furnace temperature of 1050°C and then cooled in air.

[0042] At various surface temperatures, the pipe ends were cut with a saw having the cutters shown in Table 2 under the conditions shown in Table 3. After cutting, the occurrence of cracks and burrs were evaluated by the following evaluation methods. In addition, the surface temperature of the tube was measured with a radiation thermometer.

[0043] Crack Evaluation Method

[0044] Pickling is carried out after removing scale on the inner and outer surfaces of the tube with a shot blasting machine, and the presence or absence of cracks is evaluated by visually inspecting the en...

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Abstract

Disclosed is a method for production of a martensitic stainless steel pipe having the following chemical composition (by mass): C: 0.15-0.22%; Si: 0.10-1.00%; Mn: 0.10-1.00%; Cr: 12.00-14.00%; N: 0.01-0.05%; P: 0.020% or less; and S: 0.010% or less, with the remainder being Fe and unavoidable impurities. After the martensitic stainless steel pipe is produced, the steel pipe is air-cooled until the temperature of the outer surface of the steel pipe becomes 135 to 175 DEG C, and the end part of the pipe is then cut. The crack sensitivity of the steel pipe can be reduced. By cutting the steel pipe at a temperature falling within a specific range, the cracking of the cut section can be prevented and the formation of burr can also be prevented.

Description

technical field [0001] The invention relates to a method for manufacturing a martensitic stainless steel pipe. Background technique [0002] Due to the high crack sensitivity of martensitic stainless steel pipes such as 13Cr, cracks will occur when the end of the pipe is cut with a saw. Conventionally, in order to solve this problem, the tube is cooled to a temperature of the outer surface (hereinafter, simply referred to as "surface") of the tube before cutting to 130°C or lower, preferably 50°C or lower. [0003] Patent Document 1 discloses an invention in which, in order to prevent cracks at the pipe end of the martensitic stainless steel pipe, the temperature of the martensitic stainless steel pipe after hot working is cooled in air to a temperature below the completion temperature of the martensitic transformation, Then corrective cooling is carried out with water cooling, and then the cutting process starts. [0004] Patent Document 1: Japanese Patent Application Lai...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D8/00C22C38/18C21D8/10C22C38/54C21D9/08B21B23/00C22C38/00
CPCC21D9/08C21D8/00C22C38/02C22C38/04C21D8/10C22C38/18C22C38/001
Inventor 斋藤建一
Owner NIPPON STEEL CORP
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