Cold forging gear steel containing Nb and B and preparation method thereof

A gear steel, cold forging technology, applied in the field of gear steel, can solve the problems of coarse grain and low hardness

Pending Publication Date: 2021-12-07
SHOUGANG CORPORATION
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, traditional gear steel raw materials have been difficult to meet the requirements of cold precision forging technology, and a new type of gear steel is urgently needed. On the bas

Method used

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  • Cold forging gear steel containing Nb and B and preparation method thereof
  • Cold forging gear steel containing Nb and B and preparation method thereof
  • Cold forging gear steel containing Nb and B and preparation method thereof

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preparation example Construction

[0048] A kind of preparation method that contains Nb, B cold forging gear steel, described method comprises:

[0049] The smelted molten steel is sequentially poured and continuously cast to obtain a slab;

[0050] Heating the cast slab, and finally descaling to obtain the cast slab after descaling;

[0051] Rolling and cooling the cast slab after descaling in sequence to obtain the gear steel;

[0052] The rolling includes rough rolling and finish rolling, the starting temperature of the rough rolling is 1050-1100°C, the temperature of the finish rolling is 850-950°C, and the total deformation of the finish rolling unit is 40%- 60%.

[0053] Utilize the pinning effect of precipitates formed after cold forging and carburizing to prevent the growth of austenite grains, thereby avoiding the local coarse grain phenomenon, and at the same time, it can compensate for the decrease in hardenability after reducing the content of Si and Mn to meet the requirements of gears. Hardenab...

Embodiment 1

[0069] In this embodiment, the constituent elements and mass percentages used in the gear steel are: C 0.18%, Si 0.07%, Mn 0.50%, P 0.011%, S 0.005%, Cr 1.15%, Nb 0.02%, B 0.0015%, Cu 0.11%, N0.0040%, the balance is Fe and unavoidable impurities.

[0070] The production specification is Φ60mm new cold forged gear steel. The specific control parameters are:

[0071] (1) Electric furnace is used for smelting, and the carbon content (mass fraction) at the end of tapping is controlled at 0.12%; then it enters the LF furnace for out-of-furnace refining, and feeds aluminum wire 5m / t after the seat ladle, and controls the target aluminum content of the primary composition J1 of refining to the station When reaching 0.060%, add lime and fluorite according to the slag condition and the sulfur content during tapping to ensure good fluidity of the slag; then carry out VD vacuum degassing on the molten steel, the pumping time is 4min, and the vacuum holding time is less than 67Pa Up to 1...

Embodiment 2

[0075] In this embodiment, the constituent elements and mass percentages used in the gear steel are: C 0.18%, Si 0.07%, Mn 0.50%, P 0.011%, S 0.005%, Cr 1.15%, Nb 0.02%, B 0.0015%, Ti 0.05%, Al0.025%, Cu 0.11%, N 0.0045%, the balance is Fe and unavoidable impurities.

[0076] The production specification is Φ120mm new type cold forged gear steel. The specific control parameters are:

[0077] (1) Converter smelting is adopted, and the carbon content (mass fraction) at the end of tapping is controlled at 0.08%; then it enters the LF furnace for out-of-furnace refining, and feeds aluminum wire 4m / t after the seat ladle, and controls the target aluminum content of the primary composition J1 of the refining station Reach 0.045%, add lime and fluorite according to slag condition and sulfur content during tapping to ensure good slag fluidity; then carry out VOD vacuum degassing on molten steel, pumping time is 7min, less than 67Pa vacuum holding time up to 10min.

[0078] (2) Prote...

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Abstract

The invention belongs to the technical field of gear steel, and relates to cold forging gear steel containing Nb and B. The gear steel comprises the following components in percentage by mass: 0.15%-0.25% of C, 0.05%-0.40% of Si, 0.30%-1.40% of Mn, 0-0.03% of P, 0-0.035% of S, 0.80%-1.50% of Cr, 0.01%-0.05% of Nb, 0.0005%-0.0030% of B, 0-0.05% of Ti, 0-0.045% of Al, 0-0.15% of Cu, 0-0.0150% of N and the balance of Fe and inevitable impurities. By adding Nb and B elements and utilizing the pinning effect of a precipitated phase formed after cold forging carburization, the growth of austenite grains is prevented, so that the local coarse grain phenomenon is avoided, and meanwhile, the reduction of the hardenability after the content of Si and Mn is reduced can be made up to meet the hardenability requirement of a gear; and the number of deformation zones in the austenite grains is increased, a large number of nucleation positions are provided for ferrite phase transformation, ferrite phase transformation is promoted, the proportion of ferrite in a rolled metal structure is increased, and cold-state deformation resistance is reduced.

Description

technical field [0001] The invention belongs to the technical field of gear steel, in particular to a cold forging gear steel containing Nb and B and a preparation method thereof. Background technique [0002] The steel for primary cold-rolled cover and unpacking is a cold-rolled low-carbon steel plate or steel strip coated with tin or chromium on both sides obtained through electroplating, and is mainly used for beverage cans, food cans, spray cans and chemical cans, etc. field. [0003] In recent years, with the rapid development of the mechanical processing industry, cold forging technology, as a less / no cutting process with less consumables, high efficiency and superior performance, has been widely used in civil industries such as automobiles, machine tools, and instruments, as well as in defense industry systems. application. The huge technical superiority and good economic benefits exhibited by cold forging technology have gradually become the development direction o...

Claims

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Application Information

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IPC IPC(8): C22C38/02C22C38/04C22C38/26C22C38/32C22C38/28C22C38/06C22C38/20C22C33/06B21B37/74C21D8/00
CPCC22C38/02C22C38/04C22C38/26C22C38/32C22C38/28C22C38/06C22C38/20C22C38/001C22C33/06B21B37/74C21D8/005C21D2211/001C21D2211/005C21D2211/009
Inventor 晁月林徐士新孙齐松佟倩张吉周马跃吕迺冰穆相林丁宁刘洋洋王晓晨
Owner SHOUGANG CORPORATION
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