Steel alloy with tailored hardenability

Patent metadata

Field	Value
Publication number	US-2018044769-A1
Application number	US-201615235922-A
Country	US
Kind code	A1
Filing date	Aug 12, 2016
Priority date	Aug 12, 2016
Publication date	Feb 15, 2018
Grant date	—

Abstract

An alloy with tailored hardenability includes carbon, silicon, manganese, nickel, molybdenum, chromium, vanadium, and cobalt. A time and temperature transformation diagram of the alloy has a bainite nose and a ferrite nose that occur at approximately the same time at approximately 4 seconds at temperatures of about 750 K and 950 K, respectively.

First claim

What is claimed is:

1 . An alloy with tailored hardenability comprising:
carbon; silicon niobium; manganese; molybdenum; and chromium, and
wherein a time and temperature transformation diagram of the alloy has a bainite nose and a ferrite nose that occur at approximately the same time at temperatures of approximately 750 K and 950 K, respectively.

2 . The alloy of claim 1 wherein boron is absent from the alloy.

3 . The alloy of claim 1 wherein the bainite nose and the ferrite nose occur at about four seconds.

4 . The alloy of claim 1 wherein the silicon is present in an amount of about 0.6% by weight.

5 . The alloy of claim 1 wherein the niobium is present in an amount of about 0.6% by weight.

6 . The alloy of claim 1 wherein the carbon is present in an amount of about 0.2% by weight, the silicon is present in an amount of about 0.6% by weight, the manganese is present in an amount of about 1.2% by weight, the molybdenum is present in an amount of about 0.1% by weight, the chromium is present in an amount of about 0.4% by weight.

7 . The alloy of claim 1 wherein the carbon is present in an amount of about 0.2% by weight, the niobium is present in an amount of about 0.6% by weight, the manganese is present in an amount of about 1.2% by weight, the molybdenum is present in an amount of about 0.1% by weight, the chromium is present in an amount of about 0.4% by weight.

8 . The alloy of claim 1 wherein the alloy has an austenitizing temperature of about 1123 K to 1223 K.

9 . The alloy of claim 1 wherein the alloy has a hardness of about 450-500 HV as martensite, 400-500 HV as a combination of martensite and bainite, 240-400 HV as a combination of ferrite, bainite and martensite, and less than 200 HV as a combination of ferrite, pearlite, and bainite.

10 . The alloy of claim 1 wherein the alloy has a modulus of elasticity typical of press hardened steel of about 200 GPa.

11 . The alloy of claim 1 wherein the alloy has a tensile strength of about the alloy has a tensile strength of about 1400-1550 MPa as martensite, 1300-1500 MPa as a combination of martensite and bainite, 1000-1300 MPa as a combination of ferrite, bainite and martensite, and less than 1000 MPa as a combination of ferrite, pearlite, and bainite.

12 . A machine component with tailored hardenability comprising:
an alloy including: carbon; silicon; niobium; manganese; molybdenum; and chromium, and
wherein a time and temperature transformation diagram of the alloy has a bainite nose and a ferrite nose that occur at approximately the same time at temperatures of approximately 750 K and 950 K, respectively

13 . The machine component of claim 12 wherein boron is absent from the alloy.

14 . The machine component of claim 12 wherein the bainite nose and the ferrite nose occur at about four seconds.

15 . The machine component of claim 12 wherein the carbon is present in an amount of about 0.2% by weight, the silicon is present in an amount of about 0.6% by weight, the manganese is present in an amount of about 1.2% by weight, the molybdenum is present in an amount of about 0.1% by weight, the chromium is present in an amount of about 0.4% by weight.

16 . The machine component of claim 12 wherein the carbon is present in an amount of about 0.2% by weight, the niobium is present in an amount of about 0.06% by weight, the silicon is present in an amount of about 0.06% by weight, the manganese is present in an amount of about 1.2% by weight, the molybdenum is present in an amount of about 0.1% by weight, the chromium is present in an amount of about 0.4% by weight.

17 . The machine component of claim 12 wherein over a region of about one cm of the machine component, quenching of the alloy varies from about 2° K per second to about 50° K per second.

18 . The machine component of claim 12 wherein the alloy has an austenitizing temperature of about 1123 K to 1223 K.

19 . An alloy with tailored hardenability consisting of in % by weight:
0.2% carbon; 0.6% silicon; 1.2% manganese; 0.1% molybdenum; and 0.4% chromium, and
wherein a time and temperature transformation diagram of the alloy has a bainite nose and a ferrite nose that occur at approximately the same time.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Enloe Charles M
• Wang Jianfeng
• Horvath Curt D
• Singh Jatinder P

Classifications

• C21D2211/008

  Martensite · CPC title

• C21D2211/00

  Microstructure comprising significant phases · CPC title

• C22C38/22 Primary

  with molybdenum or tungsten · CPC title

• C21D2211/002

  Bainite · CPC title

• C22C38/04

  containing manganese · CPC title