Y55 mark free-cutting steel plate and manufacture method thereof

A manufacturing method and free-cutting technology, applied in the field of medium-thick steel plate manufacturing, can solve problems such as the inability to meet the large demand for free-cutting steel plates, the surface quality of cast slabs and scrap steel plates, and the huge impact on production costs, achieving light oxide segregation and improving metal The effect of low yield and low production cost

Active Publication Date: 2013-02-13
XINYU IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the high sulfur content of free-cutting steel, poor control of the slab continuous casting process can easily produce surface longitudinal cracks, which has a huge impact on the pass rate and production cost of the slab. The main manifestations are: 1) Severe surface cracks lead to the scrapping of the slab 2) Severe longitudinal cracks on the surface of the slab can easily lead to cracks and breakouts, damage equipment, and affect production; 3) High-strength free-cutting steel has high carbon content, and the plate The slab must be hot delivered and hot charged, otherwise the slab will break naturally after cooling
Therefore, there is no report on the production of sulfur-containing free-cutting steel by continuous casting of slabs at home and abroad. They all use die-casting and rolling sulfur-containing free-cutting steel plates, which cannot meet the large demand for free-cutting steel plates in the machining industry.

Method used

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  • Y55 mark free-cutting steel plate and manufacture method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Example 1: A Y55 brand free-cutting steel plate in this embodiment is composed of the following components in weight percentage: C 0.58%, Mn 1.10%, Si 0.08%, P 0.025%, S 0.050%, Ca 0.0019%, Ti 0.013%, Alt 0.008%, the balance is iron Fe and unavoidable impurities. The thickness of the billet is 420mm, and the thickness of the steel plate after rolling is 115mm.

[0021] The smelting, continuous casting, heating, rolling and stack cooling processes of the present embodiment are as follows:

[0022] 1) Smelting process: Converter decarburization, dephosphorization, no desulfurization, weak deoxidation at the outbound station, no aluminum wire feeding at the argon station, and oxygen content of 30ppm. In order to increase the yield of ferrous sulfide alloy, no lime is added for refining, 450kg of refining slag and 500kg of submerged arc slag are added. The yield of ferrous sulfide alloy smelted this time is 73.4%. Outbound temperature 1550℃;

[0023] 2) Continuous cast...

Embodiment 2

[0027] Example 2: A continuous casting slab of this embodiment produces Y55 brand free-cutting steel plate, which is composed of the following components in weight percentage: C 0.50%, Mn 0.9%, Si 0.15%, P 0.045%, S 0.08%, Ca 0.0015% , Ti 0.010%, Alt 0.015%, and the rest is iron Fe and unavoidable impurities. The thickness of the billet is 300mm, and the thickness of the steel plate after rolling is 85mm.

[0028] The smelting, continuous casting, heating, rolling and stack cooling processes of the present embodiment are as follows:

[0029] 1) Smelting process: converter decarburization, dephosphorization, no desulfurization, weak deoxidation at the exit station, no aluminum wire feeding at the argon station, and the oxygen content is 58ppm. No lime is added for refining, 400kg of refining slag is added, and 450kg of submerged arc slag is added. The yield of ferrous sulfide alloy smelted this time is 76.6%. The outbound temperature is 1545°C;

[0030] 2) Continuous cast...

Embodiment 3

[0034] Example 3: A kind of continuous casting slab of this embodiment produces Y55 grade free-cutting steel plate, which is composed of the following components in weight percentage: C 0.53%, Mn 0.70%, Si 0.05%, P 0.038%, S 0.15%, Ca 0.0040% , Ti 0.011%, Alt 0.003%, and the rest is iron Fe and unavoidable impurities. The thickness of the billet is 250mm, and the thickness of the steel plate after rolling is 55mm.

[0035] The smelting, continuous casting, heating, rolling and stack cooling processes of the present embodiment are as follows:

[0036]1) Smelting process: converter decarburization, dephosphorization, no desulfurization, weak deoxidation at the exit station, no aluminum wire feeding at the argon station, and oxygen content of 70ppm. No lime is added for refining, 350kg of refining slag is added, and 400kg of submerged arc slag is added. The yield of ferrous sulfide alloy smelted this time is 81.6%. The outbound temperature is 1540°C;

[0037] 2) Continuous ...

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Abstract

The invention discloses a Y55 mark free-cutting steel plate and a manufacture method thereof. The steel plate comprises the following chemical components by weight percent: 0.50-0.58% of C, 0.05-0.15% of Si, 0.70-1.10% of Mn, less than or equal to 0.040% of P, 0.050-0.150% of S, 0.010-0.020% of Ti, 0.0015-0.0040% of Ca, and less than or equal to 0.015% of Alt. The manufacture method comprises the following steps that: desulfuration is not performed on molten iron in a converter, wherein the oxygen content is controlled at 30-70ppm; the temperature of a tundish is 1505-1525 DEG C, and the plate blank pull speed is 0.70-1.0m / min; the total heating time is controlled according to 0.95-10.5min / mm of the thickness of a casting blank; the initial blanking temperature is 1000-1050 DEG C, and the final rolling temperature is greater than or equal to 980 DEG C; and the steel plate is slowly cooled after hot rolling, wherein the slow cooling time is more than or equal to 48h. According to the invention, the steel plate is good in cutting performance, and the manufacture method is high in production efficiency.

Description

technical field [0001] The invention relates to the technical field of medium-thick steel plate manufacturing, in particular to a Y55 free-cutting steel plate and a manufacturing method thereof. Background technique [0002] With the continuous development of mechanical cutting processing in the direction of automation, high speed and precision, manufacturing enterprises have put forward requirements for improved processing performance and higher strength of free-cutting steel plates, so as to reduce tool loss and improve the service life of machined parts. China began to produce sulfur-based free-cutting steels in the 1950s, and formulated the industry standard YB 191-75 for free-cutting steels in 1975. Since the 1970s, the trial production of calcium-based, titanium-based and free-cutting steels containing lead, selenium, tellurium or rare earths has begun. The current implementation standard is GB / T 8731-2008, and the grades of sulfur-based free-cutting steels in the stan...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/14C21D8/02B22D11/22B22D11/20B22D11/18
Inventor 赵和明夏文勇王柏跃刘小林董富军罗仁辉马庆国袁静操瑞宏肖年根王学林
Owner XINYU IRON & STEEL CO LTD
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