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High-strength and high-toughness seamless steel tube and preparation method thereof

A seamless steel pipe, high strength and toughness technology, applied in metal rolling and other directions, can solve the problem of large outer diameter of steel pipe, achieve the effect of improving welding performance, improving surface quality, saving cycle and cost

Active Publication Date: 2022-02-15
CHENGDU ADVANCED METAL MATERIALS IND TECH RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For the preparation of large crawler cranes with a lifting capacity of more than 400t, the outer diameter and wall thickness of the steel pipe used for the main rotating pipe of the crane jib are larger, and the service conditions require that the seamless steel pipe not only has higher strength and toughness, general seamless steel pipes cannot meet the conditions of use

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0025] The preparation method of the above-mentioned high-strength and toughness seamless steel pipe includes successively the steps of continuous casting round billet smelting, tube billet rolling and heat treatment to obtain the high-strength and toughness seamless steel pipe.

[0026] Continuous casting round billet smelting includes electric furnace smelting, out-of-furnace refining, vacuum refining treatment, and continuous casting round billet;

[0027] Among them, the electric furnace smelting is: the carbon at the end of the electric furnace should be ≥0.06%, and the tapping temperature is 1620-1660 °C;

[0028] Refining outside the furnace is as follows: rapid production of white slag, white slag retention time ≥ 20min, adding a small amount of FeTi alloy for micro-titanium treatment before tapping;

[0029] Vacuum refining is: vacuum degree ≤ 67Pa, holding time ≥ 15min, net blowing time ≥ 10min, VD tapping temperature 1575-1595℃.

[0030] The continuous casting proc...

Embodiment 1

[0044] The production size of this embodiment is a high-strength and toughness seamless steel pipe with a specification of φ219.1×17mm, and the steps include:

[0045] A. Continuous casting round billet smelting

[0046] Smelting process route: electric furnace smelting→outside furnace refining→vacuum refining→φ220 continuous casting round billet.

[0047] Smelting production requirements:

[0048] ①The carbon at the end of the electric furnace should be ≥0.08%, and the tapping temperature is 1620-1640°C.

[0049] ②Deoxidation alloying: SiAlBaCa or LGB added in the amount of 3.0-4.0kg / t, Al added in the amount of 3.0-4.0kg / t.

[0050] ③ LF furnace refining: rapid production of white slag, white slag retention time ≥ 25min, and check every 5 minutes; add 4.0Kg / t steel FeTi for micro-titanium treatment before tapping;

[0051]④VD refining: vacuum degree ≤67Pa, holding time ≥20min, net blowing time ≥15min; VD tapping temperature: 1575~1585℃.

[0052] ⑤ The pouring liquid leve...

Embodiment 2

[0071] The production size of this embodiment is 101.6*6.3mm specification high-strength toughness seamless steel pipe, and its steps include:

[0072] A. Continuous casting round billet smelting

[0073] Smelting process route: electric furnace smelting→outside furnace refining→vacuum refining→φ200 continuous casting round billet.

[0074] Smelting production requirements:

[0075] ① The carbon at the end point of the electric furnace is ≥0.09%, and the tapping temperature is 1640-1660°C.

[0076] ②Deoxidation alloying: SiAlBaCa or LGB added at 2.0-3.0kg / t, Al added at 2.0-3.0kg / t.

[0077] ③ LF furnace refining: rapid production of white slag, white slag retention time ≥ 15min, and check every 5 minutes; add 1.5Kg / t steel FeTi for micro-titanium treatment before tapping;

[0078] ④VD refining: vacuum degree ≤67Pa, holding time ≥15min, net blowing time ≥10min; VD tapping temperature: 1585~1595℃.

[0079] ⑤ The pouring liquid level of the electric furnace continuous castin...

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Abstract

The invention belongs to the technical field of ferrous metallurgy, and particularly relates to a high-strength and high-toughness seamless steel tube and a preparation method thereof. The technical problem to be solved by the invention is to provide a seamless steel tube with high strength and toughness and a preparation method thereof. The seamless steel tube comprises the following chemical components in percentage by weight: 0.15 to 0.20 percent of C, 0.20 to 0.50 percent of Si, 1.10 to 1.50 percent of Mn, less than or equal to 0.025 percent of P, less than or equal to 0.015 percent of S, 0.40 to 1.20 percent of Cr, 0.30 to 1.00 percent of Mo and the like. The preparation method of the high-strength and high-toughness seamless steel tube comprises the following steps of continuous casting round billet smelting, tube billet rolling and heat treatment. Chemical components of the high-strength and high-toughness seamless steel pipe contain Cr, Ni, Mo and Nb alloy elements, micro titanium treatment is carried out, the welding performance of the steel pipe is improved, meanwhile, reasonable smelting, rolling and heat treatment processes are formulated, and the high-strength and high-toughness seamless steel pipe with the yield strength larger than or equal to 1000 MPa, the tensile strength larger than or equal to 1100 MPa, the ductility larger than or equal to 15%, the longitudinal impact energy larger than or equal to 120 J at the temperature of-20 DEG C and the longitudinal impact energy larger than or equal to 75 J at the temperature of -40 DEG C is obtained.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy, and in particular relates to a high-strength and toughness seamless steel pipe and a preparation method thereof. Background technique [0002] Crawler crane is a heavy-duty self-propelled crane used in high-rise building construction. It is a lifting operation machinery product with high technical content, complicated preparation process and unique performance in construction machinery. It is widely used in bridges, power generation equipment, oil refining equipment, wind power The construction of projects such as generating sets and offshore working platforms. [0003] At present, the maximum lifting capacity of crawler cranes has exceeded 1000t. As an important part of the crawler crane, the combined jib frame is the key part for carrying and conveying. The jib frame is generally made of a seamless steel pipe with a length of about 11m as the main spiral pipe and the web pipe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/44C22C38/46C22C38/48C22C38/06C22C38/42C22C38/50C22C33/06C21D8/10C21D1/18B21B19/04B21D3/00
CPCC22C38/02C22C38/04C22C38/44C22C38/46C22C38/48C22C38/06C22C38/42C22C38/50C22C33/06C21D8/105C21D1/18B21B19/04B21D3/00Y02P10/20
Inventor 林发驹李雄
Owner CHENGDU ADVANCED METAL MATERIALS IND TECH RES INST CO LTD
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