Steel for tracked undercarriage component, and track link

Patent metadata

Field	Value
Publication number	US-9790578-B2
Application number	US-201414764626-A
Country	US
Kind code	B2
Filing date	May 8, 2014
Priority date	May 17, 2013
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

A steel for a tracked undercarriage component is used as a material constituting a track link ( 9 ), for example, and contains: not less than 0.39% by mass and not more than 0.45% by mass of carbon, not less than 0.2% by mass and not more than 1.0% by mass of silicon, not less than 0.10% by mass and not more than 0.90% by mass of manganese, not less than 0.002% by mass and not more than 0.005% by mass of sulfur, not less than 0.1% by mass and not more than 3.0% by mass of nickel, not less than 0.70% by mass and not more than 1.50% by mass of chromium, and not less than 0.10% by mass and not more than 0.60% by mass of molybdenum, with the balance made of iron and unavoidable impurities.

First claim

The invention claimed is:

1. A steel for a tracked undercarriage component used adapted for use as a material constituting a tracked undercarriage component, the steel containing:
not less than 0.39% by mass and not more than 0.45% by mass of carbon, not less than 0.2% by mass and not more than 1.0% by mass of silicon, not less than 0.10% by mass and not more than 0.90% by mass of manganese, not less than 0.002% by mass and not more than 0.005% by mass of sulfur, not less than 0.1% by mass and not more than 3.0% by mass of nickel, not less than 0.70% by mass and not more than 1.50% by mass of chromium, and not less than 0.10% by mass and not more than 0.60% by mass of molybdenum, with the balance consisting of iron and unavoidable impurities.

2. The steel for a tracked undercarriage component according to claim 1 , further containing at least one species selected from the group consisting of not less than 0.05% by mass and not more than 0.20% by mass of vanadium, not less than 0.005% by mass and not more than 0.05% by mass of niobium, not less than 0.01% by mass and not more than 0.15% by mass of zirconium, not less than 0.01% by mass and not more than 0.10% by mass of titanium, and not less than 0.1% by mass and not more than 2.0% by mass of cobalt.

3. The steel for a tracked undercarriage component according to claim 1 , further containing not less than 0.001% by mass and not more than 0.005% by mass of boron.

4. The steel for a tracked undercarriage component according to claim 1 , wherein a value of Ra as a sum of a half of the carbon content, a quadruple of the sulfur content, and the content of phosphorus as an unavoidable impurity is 0.25% by mass or less.

5. The steel for a tracked undercarriage component according to claim 4 , wherein the value of said Ra is 0.22% by mass or more.

6. The steel for a tracked undercarriage component according to claim 1 , adapted for use as a material constituting a track link.

7. A track link made of a steel containing not less than 0.39% by mass and not more than 0.45% by mass of carbon, not less than 0.2% by mass and not more than 1.0% by mass of silicon, not less than 0.10% by mass and not more than 0.90% by mass of manganese, not less than 0.002% by mass and not more than 0.005% by mass of sulfur, not less than 0.1% by mass and not more than 3.0% by mass of nickel, not less than 0.70% by mass and not more than 1.50% by mass of chromium, and not less than 0.10% by mass and not more than 0.60% by mass of molybdenum, with the balance consisting of iron and unavoidable impurities, the track link comprising:
a base region; and
a hardened region formed to include a rail surface and having a higher hardness as compared to said base region,
said hardened region having a hardness of HRC 57 or more and a reduction of area of 40% or more.

8. The track link according to claim 7 , wherein said steel further contains at least one species selected from the group consisting of not less than 0.05% by mass and not more than 0.20% by mass of vanadium, not less than 0.005% by mass and not more than 0.05% by mass of niobium, not less than 0.01% by mass and not more than 0.15% by mass of zirconium, not less than 0.01% by mass and not more than 0.10% by mass of titanium, and not less than 0.1% by mass and not more than 2.0% by mass of cobalt.

9. The track link according to claim 7 , wherein said steel further contains not less than 0.001% by mass and not more than 0.005% by mass of boron.

10. The track link according to claim 7 , wherein a value of Ra as a sum of a half of the carbon content, a quadruple of the sulfur content, and the content of phosphorus as an unavoidable impurity in said steel is 0.25% by mass or less.

11. The track link according to claim 10 , wherein the value of said Ra is 0.22% by mass or more.

12. The track link according to claim 7 , wherein said base region has a hardness of not less than HRC 30 and not more than HRC 45.

Assignees

• Komatsu Mfg Co Ltd

Inventors

• Amada Eiji
• Maeda Kazuo
• Kajiura Takeji

Classifications

• B62D55/21

  Links connected by transverse pivot pins · CPC title

• C21D2221/00

  Treating localised areas of an article · CPC title

• C22C38/06

  containing aluminium · CPC title

• C22C38/08

  containing nickel {(C22C38/105 takes precedence)} · CPC title

• C22C38/12

  containing tungsten, tantalum, molybdenum, vanadium, or niobium · CPC title