Market application and alloy type of gear steel

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• Tag: alloy type , gear steel , market application
Market application and alloy type of gear steel Gear products are the key basic parts of the machinery industry, and the main transmission components of most complete sets of machinery are gear tra...

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Market application and alloy type of gear steel

Gear products are the key basic parts of the machinery industry, and the main transmission components of most complete sets of machinery are gear transmissions. In recent years, my country's gear industry has developed rapidly, and the gear industry has become a leading industry in the field of basic parts of China's mechanical general parts. China has become a veritable world gear manufacturing country. The main upstream industry of the gear industry is the steel industry. Steel is the main source of raw materials for gear products. Therefore, changes in gear steel have a direct impact on the gear industry.

1. Application and market of gear steel

(1) The application of gear steel The use of gear steel has a wide coverage. my country's gear industry is composed of three parts: train gears, industrial gears and gear equipment. Among them, train gears have a market share of 60%; industrial gears are composed of industrial general-purpose, special-purpose and special gears, with market shares of 18%, 12%, and 8% respectively; gear equipment accounts for 2% of the market share.

Vehicle gears are mainly gears for automobiles, motorcycles, agricultural transport vehicles, agricultural machinery, and construction machinery, mainly automobile gears. Among vehicle gears, automobile gears account for 60%, motorcycles 3.5%, agricultural transport vehicles 15%, agricultural machinery 12%, and construction machinery 9.5%.

Industrial gear is a gear device (such as a reducer) that is used by industrial enterprises with various complete sets of mechanical equipment, accounting for about 40% of the total gear.

(2) Market demand for gear steel In 2018, the output of gear steel in my country reached 3.47 million tons. From the perspective of supply and demand in the domestic market, domestic gear steel can basically meet the demand for domestic automobile and construction machinery gears in quantity. With the steady growth of my country's economy and the continuous development of the machinery manufacturing industry, high-grade gear steels for automobile and other manufacturing industries are the key special steel varieties for key development; high-strength and high-toughness automotive steels, high-quality bearing steels, and gears with longer service life The increasing volume will undoubtedly inject strong power and vitality into the gear steel market.

2. Production overview of gear steel in my country

The production of gear steel in my country is mainly concentrated in special steel enterprises, accounting for about 35% of the total.

(1)Production process route There are basically two types of production process routes for gear steel in my country:

1) EF (or BOF) + LF (or VAD or RH) refining → molding into ingot → blooming (or forging) → tandem rolling mill or semi-tandem rolling mill finished product → finishing → inspection and storage;

2) UHP (or EBT) + LF/VD refining → alloy steel billet continuous casting → (semi) continuous rolling mill finished product → finishing → inspection and storage.

(2) Main steel grades

According to the classification of alloy series, gear steel can be divided into Cr-Mn-Ti series, Cr series, Mn-Cr series, Cr-Mo series, Cr-Mn-B series and Cr-Ni-Mo series.

1) Cr-Mn-Ti series: mainly 20CrMnTiH, at the same time, according to different models and the processing technology of different gear factories, 20CrMnTm can be divided into H1, H2, H3 and other sub-steel series with different hardenability bandwidths. And on the basis of the original 20CrMnTi, FAW and relevant metallurgical plants have developed 16CrMnTiH and 18CrMnTiH steels for the production of gears for Hongqi cars.

2)Cr series gear steel: The steel grade is SCr420H. Compared with 20CrH in the Chinese GB/T5216-85 standard, the content of Mn and Cr is increased, and the hardenability is slightly higher.

3)Cr-Mn series gear steel: steel grades are 16MnCr5, 20MnCr5, 25MnCr5, 28MnCr5, 27MnCr5, mainly used for Audi, Jetta, Santana and Fukang car gears, Iveco minibuses and some imported heavy truck gears.

4)Cr-Mo series gear steel: the steel grades are SCM415H, SCM420H, SCM822H1(H2), 16CD4, 20CD4, 27CD4, 30CD4 and other grades, mainly used in the production of gears for Peugeot cars, Isuzu CMB and 153 medium trucks.

5)Cr-Mn-B series gear steel: the main varieties are ZF6 (16CrMnBH), ZF7 (B) (18CrMnBH, 20CrMnBH) from Germany. ZF steel is B-treated Cr-Mn series gear steel. Mainly used for Steyr heavy duty truck gears. The role of B in this type of steel is mainly to form spherical BN, reduce the amount of dissolved N in the steel, and improve the toughness of the steel, while B in the traditional carburized boron steel mainly plays the role of improving the hardenability.

6)Cr-Ni-Mo series gear steel: The steel grades are mainly SAE8620H, SAE8627H, SAE4320H American steel grade and ZFlA (or 17CrNiMo6) German steel grade, which are used for Cherokee cars and Steyr truck gears.

In view of the differences in resources and production process conditions in various countries, the gear steel alloy series used in each country and region is different, for example: Germany uses Mn-Cr series and Cr-Mn-B series (16MnCr5, 20MnCr5, 25MnCr5, 28MnCr5, ZF6 , ZF7, ZF7B); Japan uses Cr series and Cr-Mo3 series (SCr420H, SCM415H, SCM420H, SCM822H); the United States adopts Cr-Ni-Mo series (SAE8617H, SAE8620H); France adopts Cr-Ni series (19CN5) and Cr -Mo series (20CD4, 27CD4, 30CD4) gear steel; 20CrMnTi gear steel is widely used in China.