Chuo Hatsujo Kabushiki Kaisha

Aichi Steel Works, Ltd.

Toyota Jidosha Kabushiki Kaisha

Honda Giken Kogyo Kabushiki Kaisha

Nippon Steel Corporation

Toshio Ozone

Ryohei Kobayashi

Mamoru Kurimoto

Toshiro Yamamoto

Masayuki Hashimura

Ikuo Ochiai

Osamu Nakano

Takashi Otowa

Taisuke Nishimura

Chikatoshi Maeda

Hiroshi Yarita

Atsushi Sugimoto

Masaaki Mikura

Shigeru Yasuda

Makoto Kawagoe

Masato Yanase

The present invention provides, at low cost, a valve spring steel having a tensile strength as high as 210 to 240 kgf/mm.sup.2 after oil tempering. The high strength spring steel comprises, based on weight, 0.65 to 0.85% of C, 1.90 to 2.40% of Si, 0.50 to 1.00% of Mn, 0.70 to 1.30% of Cr, 0.10 to 0.30% of Mo, 0.20 to 0.50% of V, 0.01 to 0.04% of Nb and the balance Fe and unavoidable impurities and is subjected to heating at temperature of 1,050 to 1,250.degree. C. and then to rolling so that carbides in the steel have a size of up to 0.15 .mu.m in terms of equivalent circle. A valve spring having a tensile strength as high as 210 to 240 kgf/mm.sup.2 after oil tempering and stabilized quality can be produced while the material cost is greatly reduced by decreasing costly alloying components as much as possible.

High strength spring steel and process for producing same

A spring steel having a good durability and a good sag-resistance consisting essentially of by weight 0.35-0.55% carbon, 1.80-3.00% silicon, 0.50-1.50% manganese, 0.50-3.00% nickel, 0.10-1.50% chromium, 0.01-0.05% aluminum and 0.010-0.025% nitrogen, the remainder being iron and inevitable impurities. The spring steel has been completed for the purpose of obtaining a spring steel having a high toughness in a high hardness of not less than HRC 55 and having a good sag-resistance, in particular examining the contents of nickel, chromium and nitrogen in addition to the carbon content.

Spring steel having good durability and sag-resistance

A spring steel having a good sag-resistance comprises by weight 0.5-0.8% carbon, 0.5-1.4% silicon, 0.5-1.5% manganese and a member or members selected from a group consisting of 0.05-0.5% vanadium, 0.05-0.5% niobium and 0.05-0.5% molybdenum, the remainder being iron together with impurities. The steel may further contain a member or members selected from a group consisting 0.0005-0.01% boron, 0.2-2.0% nickel and not greater than 0.3% rare-earth elements and/or a member or members selected from a group consisting of 0.02-0.1% titanium and 0.02-0.1% zirconium.

Process of treating steel for a vehicle suspension spring to improve

A spring steel having a good sag-resistance and a good hardenability comprises by weight 0.5-0.8% carbon, 1.5-2.5% silicon, 1.6-2.5% manganese and a member or members selected from a group consisting of 0.05-0.5% vanadium, 0.05-0.5 niobium and 0.05-0.5% molybdenum, the remainder being iron together with impurities. The steel may further contain a member or members selected from a group consisting 0.0005-0.01% boron, 0.2-1.0% chromium, 0.2-2.0% nickel and not greater than 0.3% rare-earth elements and/or a member or members selected from a group consisting of 0.03-0.1% aluminum, 0.02-0.1% titanium and 0.02-0.1% zirconium.

Process for improving the sag-resistance and hardenability of a spring

A steel for use in a vehicle suspension spring having a good sag-resistance comprising by weight 0.80% carbon, 1.50-2.50% silicon, 0.50-1.50% manganese, a member or members selected from a group consisting of 0.05-0.50% vanadium, 0.05-0.50% niobium and 0.05-0.50% molybdenum, the remainder being iron together with impurities. The steel may further contain a member or members selected from a group consisting of 0.0001-0.01% 0.20-1.00% chromium, and not greater than 0.0008% nitrogen.

Method of treating steel for a vehicle suspension spring having a good

A spring steel having a good sag-resistance and a good hardenability comprises by weight 0.5-0.8% carbon, 1.5-2.5% silicon, 1.6-2.5% manganese and a member or members selected from a group consisting of 0.05-0.5% vanadium, 0.05-0.5 niobium and 0.05-0.5% mobybdenum, the remainder being iron together with impurities. The steel may further contain a member or members selected from a group consisting 0.0005-0.01% boron, 0.2-1.0% chromium, 0.2-2.0% nickel and not greater than 0.3% rare-earth elements and/or a member or members selected from a group consisting of 0.03-0.1% aluminum, 0.02-0.1% titanium and 0.02-0.1% zirconium.

Spring steel having a good sag-resistance and a good hardenability

A steel for use in a vehicle suspension spring having a good sag-resistance comprising by weight 0.50-0.80% carbon, 1.50-2.50% silicon, 0.50-1.50% manganese, a member or members selected from a group consisting of 0.05-0.50% vanadium, 0.05-0.50% niobium and 0.05-0.50% molybdenum, the remainder being iron together with impurities. The steel may further contain a member or members selected from a group consisting of 0.0001-0.01% boron and 0.20-1.00% chromium, and not greater than 0.0008% nitrogen.

Steel for a vehicle suspension spring having good sag-resistance

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Nagoya, Japan

Toshio Ozone