Process of heating lead-containing free-cutting steel

A technology of free-cutting steel and heating process, applied in the field of metallurgy, can solve the problems of insufficient utilization of heating capacity in the heating process, uneven temperature of the billet, blooming of the billet head, etc., and reduce the probability of slippage of the rolling groove and the probability of head splitting. , The effect of reducing equipment loss and improving rolling efficiency

Inactive Publication Date: 2009-02-04
NANJING NANGANG IND DEV CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of this heating process of lead-containing free-cutting steel is that the heating capacity of the heating process is not fully utilized, and the rapid heating of the soaking process makes the temperature of the billet rise rapidly from 1100-1150 °C to 1200-1250 °C, resulting in uneven temperature of the billet
Due to the strong heating of the soaking process alone, the temperature of the core of the aluminum-containing free-cutting billet will be lower than the surface temperature of the billet. In this case, there is stress inside the lead-containing free-cutting steel, and the rolling process will cause the head of the billet to bloom, resulting in Stacking steel accidents will also cause the billet to slip in the rolling groove

Method used

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  • Process of heating lead-containing free-cutting steel

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Effect test

Embodiment 1

[0030] This embodiment is a heating process of Φ5.5 lead-containing free-cutting steel, including a preheating process, a heating process, and a soaking process. The heating furnace is used for heating, the rolling speed is 94m / s, and the heating capacity is 60t / h. In the preheating process, the billet is preheated to 700°C by the waste heat of the heating section and the soaking section of the heating furnace, and the exhaust heat of the heating section and the soaking section is mainly used to draw the waste heat from the heating section and the soaking section to the end of the furnace, and the heating section The gas that is not completely burned in the soaking section continues to burn to ensure the temperature of the preheating section.

[0031] After the preheating process is completed, the lead-containing free-cutting steel billet is transported by the walking beam and enters the heating process from the preheating process. In the heating process, the billet is heated to 1...

Embodiment 2

[0039] This embodiment is a heating process for Φ6 lead-containing free-cutting steel, including a preheating process, a heating process, and a soaking process. The heating furnace is used for heating, the rolling speed is 86m / s, and the heating capacity is 64t / h. In the preheating process, the billet is preheated to 740°C by the waste heat of the heating section and soaking section of the heating furnace. The temperature of the preheating section is mainly used to draw the waste heat of the heating section and the soaking section to the end of the furnace by the exhaust of the flue gas tube, and the incompletely burned coal gas in the heating section and the soaking section continues to burn to ensure the temperature of the preheating section.

[0040] After the preheating process is completed, the lead-containing free-cutting steel billet is transported by the walking beam, and enters the heating process from the preheating process. In the heating process, the billet is heated t...

Embodiment 3

[0048] This embodiment is a heating process for Φ9 lead-containing free-cutting steel, including a preheating process, a heating process, and a soaking process. The heating furnace is used for heating, the rolling speed is 52m / s, and the heating capacity is 86t / h. In the preheating process, the billet is preheated to 780°C by the waste heat of the heating section and soaking section of the heating furnace. The temperature of the preheating section is mainly due to the exhausting force of the exhaust chimney of the furnace to draw the waste heat of the heating section and the soaking section to the end of the furnace, and the incomplete combustion of the gas in the heating section and the soaking section continues to burn, which can ensure the temperature of the preheating section.

[0049] After the preheating process is completed, the lead-containing free-cutting steel billet is transported by the walking beam, and enters the heating process from the preheating process. In the he...

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Abstract

The present invention relates to heating process in metallurgy, and is especially process of heating lead-containing free cutting steel. The heating process in a heating furnace includes a pre-heating step, a heating step, and a heat soaking step. The steel blank is first pre-heated to 700-800 deg.c in the pre-heating step with the afterheat of the heating step and the heat soaking step; then heated to 1150-1230 deg.c in the heating step with the heating burner in the heating furnace; and final heat soaked to 1150-1250 deg.c in the heat soaking step while ensuring the output temperature of 1140-1190 deg.c. Thus heated lead-containing free cutting steel has less sliding and cracking in the rolling process.

Description

Technical field [0001] The invention relates to a heating process in the field of metallurgy, in particular to a heating process for lead-containing free-cutting steel. Background technique [0002] With the rapid development of the national machining and precision instrument industries, the requirements for processing materials continue to increase, so as to ensure the surface finish of the product. The development of lead-containing free-cutting steel satisfies the needs of the processing industry well, in order to smooth rolling The heating process of lead-containing free-cutting steel wire and billet is of great significance to the normal production. Lead-containing free-cutting steel belongs to S and Pb composite free-cutting steel. The steel contains relatively high S and Pb, poor high-temperature plasticity, and has greater sensitivity to cold and hot brittleness. The range of hot brittleness is 830-1000 degrees. Avoid this temperature range as much as possible in the prod...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D9/70C21D11/00B21B37/74
Inventor 徐晓春刘文学董洪山林贵明刘百营彭学艺李孝池
Owner NANJING NANGANG IND DEV CO LTD
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