# US 4,400,225 A · Cr-Mo Steel for use as very thick plates of 75 mm or more for oil refinery, coal liquefaction and coal gasification equipment

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 4,400,225 A
- Document ID: US4400225A
- Status: Granted
- Kind: A
- Application number: 06/298,147
- Filed: 1981-08-31
- Granted: 1983-08-23
- Earliest claimed: 1980-08-29
- Assignees: Kawasaki Steel Corporation
- Inventors: Masaaki Ishikawa; Syuzo Ueda; Makoto Imanaka
- Web page: https://patentgrep.com/patent/US4400225A

## CPC

- C22C 38/32: with boron
- C22C 38/22: with molybdenum or tungsten
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

A Cr-Mo steel which is suitable for use as extremely thick plates of 75 mm or greater for pressel vessels of oil refinery, coal liquefaction and coal gasification equipment. The Cr-Mo steel includes 0.09 to 0.17 wt % of carbon, 0.03 to 0.50 wt % of silicon, 0.45 to 0.70 wt % of manganese, 1.80 to 3.40 wt % of chromium, 0.80 to 1.20 wt % of molybdenum, 0.035 to 0.1 wt % of aluminum and 0.0010 to 0.0040 wt % of boron and the balance iron and impurities inevitably mixed in steel-making processes. The Cr-Mo steel of such compositions is highly excellent in high-temperature strength, toughness and hydrogen attack resistance.

## Claims

### Claim 1

A Cr-Mo steel for use as 75 mm or more thick plates for oil refinery, coal liquefaction and coal gasification equipment, consisting of 0.09 to 0.17 wt% of carbon, 0.03 to 0.50 wt% of silicon, 0.45 to 0.70 wt% of manganese, more than 2.00 up to 3.40 wt% of chromium, 0.80 to 1.20 wt% of molybdenum, 0.035 to 0.1 wt% of aluminum, 0.0010 to 0.0040 wt% of boron and the balance iron and inevitable impurities, said steel being in bainitic condition.