Rare earth containing, high strength and high toughness seamless steel pipe used for gas cylinder and production method thereof

A technology of seamless steel pipe and production method, applied in the direction of improving process efficiency, manufacturing converters, etc., can solve problems such as unreported, unseen manufacturing method of seamless steel pipe, etc.

Inactive Publication Date: 2013-10-09
INNER MONGOLIA BAOTOU STEEL UNION
View PDF4 Cites 13 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] There is no record of this type of seamless steel pipe and its manufacturing method in the inv

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Raw materials by weight percentage are: 90% of blast furnace molten iron and 10% of high-quality steel scrap.

[0039] The sequence of the production process is: molten iron pretreatment→top-bottom combined blowing converter smelting→LF furnace refining→VD vacuum treatment→round billet continuous casting→cutting→tube heating→piercing→rolling→sizing→cooling→sawing→heat treatment → Straightening → Hydrostatic test → Flaw detection.

[0040] The specific production process is briefly described as follows:

[0041] 90 tons of blast furnace molten iron is pretreated with "magnesium powder" for desulfurization and deoxidation, so that the S content in the molten iron is reduced to less than (weight percent) 0.010%.

[0042] Mix the 90 tons of pretreated molten iron into a 100-ton top-bottom combined blown converter, add 10 tons of high-quality steel scrap, and then use the single slag process for smelting. The final slag basicity is controlled at 3.0, and silicon Manganese,...

Embodiment 2

[0062] The ratio of raw materials, production process, etc. and other process indicators of Example 2 are the same as those of Example 1, except that the chemical composition content (% by weight) of the tube blank is shown in Table 3:

[0063] The chemical composition testing result (weight %) of table 3 tube blank

[0064] C

Si

mn

P

S

Cr

Mo

Ni

V

Ti

Al

RE

0.13

0.19

1.07

0.015

0.006

1.02

0.19

0.51

0.11

0.017

0.012

0.0013

[0065] The straightening temperature of the steel pipe is 519°C, and the residual stress of the steel pipe measured by ring cutting method is 26MPa.

[0066] The test results of mechanical properties and metallographic structure of seamless steel pipes are shown in Table 4.

[0067] Table 4 Mechanical properties and metallographic structure test results of steel pipes

[0068] R t0.5 (MPa)

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

PropertyMeasurementUnit
Residual stressaaaaaaaaaa
Residual stressaaaaaaaaaa
Login to view more

Abstract

The invention provides a rare earth containing, high strength and high toughness seamless steel pipe used for a gas cylinder and a production method thereof, belonging to the technical field of metallurgy and molding. Raw materials comprises, by weight percent, 90 % of blast furnace molten iron and 10 % of high-quality scrap steel. A pipe blank comprises the following chemical components by weight percent: 0.10-0.15 of C, 0.10-0.30 of Si, 0.90-1.20 of Mn, less than or equal to 0.020 of P, less than or equal to 0.010 of S, 0.90-1.20 of Cr, 0.10-0.30 of Mo, 0.40-0.70 of Ni, 0.06-0.20 of V, 0.01-0.03 of Ti, 0.005-0.030 of Al, 0.0005-0.0100 of rare earth element RE, and the balance being Fe and undetectable trace elements. A technology proves comprises steps of pretreatment of molten iron, combined blown converter smelting, LF furnace refine, VD vacuum treatment, round ingot continuous casting, cutting, pipe blank heating, perforation, pipe rolling, sizing, cooling, sawing, heat treatment, straightening, hydrostatic test and flaw detection. Mechanical properties comprises a yield strength of 860-930 MPa, a tensile strength of 1000-1100 MPa, a yield ratio of less than or equal to 0.90, an elongation percentage of more than or equal to 19 %, a transverse impact value aKV of more than or equal to 150 J/cm<2>(-40 DEG C), a grain size of more than 8.0 grade, and a residual stress of less than or equal to 30 MPa. The product provided by the invention has characteristics of low impurity element content, small residual stress, high intensity, good toughness and excellent technology performance.

Description

1. Technical field: [0001] The invention belongs to the field of ferrous metal smelting and metal pressure processing, and relates to a rare earth-containing seamless steel pipe for high-strength and high-toughness gas cylinders and a production method thereof. 2. Background technology: [0002] A high-pressure gas cylinder is a refillable mobile steel cylinder with a nominal pressure of 10-30MPa or even higher, used to hold high-pressure gas or liquefied natural gas. There are two methods for manufacturing seamless gas cylinders, one is to use a steel billet to stretch and seal by hot stamping; Manufacturing high-pressure gas cylinders with seamless steel pipes has the advantages of low cost and good quality. [0003] In recent years, high-pressure gas cylinders are developing towards high pressure and light weight. The materials are required to have the characteristics of high strength, good toughness, and excellent process forming performance to ensure the safety and rel...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
IPC IPC(8): C22C38/50C21D8/10C21C5/35
CPCY02P10/20
Inventor 丰小冬贺景春石晓霞乔爱云金文俊张行刚
Owner INNER MONGOLIA BAOTOU STEEL UNION
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap