ND steel seamless steel pipe production process

A seamless steel pipe and production process technology, applied in the field of ND steel seamless steel pipe production process, can solve problems such as surface cracks, affect surface quality, and adverse effects on performance, achieve good surface quality, improve surface quality, and resist sulfuric acid dew point The effect of improving the corrosion ability

Inactive Publication Date: 2014-06-11
CHANGZHOU SHENGTAK SEAMLESS STEEL TUBE
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  • Summary
  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

The traditional cold-drawn steel pipe production process of ND steel seamless pipe often causes cracks on the surface, which seriously affects its surface quality and adversely affects its performance

Method used

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  • ND steel seamless steel pipe production process

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Embodiment 1)

[0037] figure 1 For process flow diagram of the present invention, this ND steel seamless steel pipe production process comprises the following steps:

[0038] (1) Cut the φ70 ND steel billet to the required length;

[0039] (2) Peel the round bar and tube billet, the peeling depth is 0.5mm~1.5mm, to remove the oxide skin on the surface;

[0040] (3) Heat the cut tube blank to 1000~1100°C, and then hold it for 40~80 minutes according to the thickness of the tube blank;

[0041] (4) The piercing is carried out on a DC frequency conversion piercing machine, the piercing temperature is 950~1050°C; the loading current is ≤1500A, and the piercing speed is 500 rpm;

[0042] (5) After the perforation is completed, use the residual heat to start the head;

[0043] (6) pickling, phosphating, and lubricating the steel pipe after step (5);

[0044] 30-35% sulfuric acid is used for pickling, the treatment time is 30-60 minutes, and the treatment temperature is 50-60°C; as a preferred ...

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Abstract

The present invention relates to a steel pipe production process, particularly to a ND steel seamless steel pipe production process, which mainly comprises: 1) carrying out a peeling treatment on a round rod pipe billet; 2) heating the round rod pipe billet to a temperature of 1000-1100 DEG C, wherein the piercing temperature is 950-1050 DEG C; 3) carrying out acid washing, phosphorization and lubrication; 4) carrying out first cold drawing; 5) carrying out acid washing, phosphorization and lubrication; 6) carrying out second cold drawing; 7) carrying out acid washing, phosphorization and lubrication; 8) carrying out intermediate annealing on the pipe; 9) carrying out acid washing, phosphorization and lubrication; 10) carrying out third cold drawing; 11) carrying out a heat treatment on the finished product; and 12) carrying out physical and chemical inspection, straightening, finishing, eddy current testing, pipe inspection, ultrasonic testing, and steel pipe stenciling and warehousing. According to the present invention, the surface of the ND steel seamless steel pipe obtained by adopting the process does not have hot cracks, and the ND steel seamless steel pipe has good sulfuric acid dew point corrosion resistance.

Description

technical field [0001] The invention relates to a steel pipe production process, in particular to a ND steel seamless steel pipe production process. Background technique [0002] Flue gas from boilers fueled by oil or coal usually contains more SO 2 and SO 3 . When the water vapor in the flue gas meets the tube walls of boiler preheaters, economizers and other process equipment such as heat exchangers and coolers, it is easy to condense into dew. Water that condenses on the pipe wall encounters SO 2 and SO 3 Generate highly corrosive sulfurous acid and sulfuric acid, causing sulfuric acid corrosion of the pipe wall, causing serious harm in industrial production. With the improvement of various boiler parameters, the increase of capacity and the use of fuel with high sulfur content, the corrosion of various pipes in the boiler in the combustion atmosphere is becoming more and more serious, especially the low-temperature sulfuric acid dew point corrosion of the boiler air...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B21C37/06
Inventor 周文庆周益鑫范琪
Owner CHANGZHOU SHENGTAK SEAMLESS STEEL TUBE
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