US4227923A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Plastic molding steel having improved resistance to corrosion by halogen gas
Assignee: Daido Steel Co Ltd
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Filing: 1978-11-27
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Granted: 1980-10-14
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Expires: 1998-11-27
Abstract
Abstract A steel which is suitable for the material of a mold used for plastic molding and which has an improved resistance to corrosion under exposure to a halogen gas generated in injection molding of a thermoplastic synthetic resin blended with a halogen-containing flame-retarding agent is obtained by shaping a steel which consists essentially of up to 0.05% carbon, up to 1.0% silicon, up to 2.0% manganese, 5.0-8.0% nickel, 11.0-15.0% chromium, 1.0-4.0% molybdenum, 0.5-4.0% copper, 0.5-2.0% cobalt and the balance iron into a mold, and then subjecting the mold to age-hardening treatment at a temperature in the range of 400°-450° C. to obtain a hardness of H R C 30 or higher. The steel may further contain a small, predetermined amount of at least one machinability-improving component such as lead, tellurium, calcium and bismuth and/or a small, predetermined amount of at least one toughness or hardness-improving component such as tungsten, boron, titanium, vanadium, niobium and tantalum.
Inventors
- 👤 Toshiyuki Watanabe
- 👤 Hisao Kamiya
- 👤 Noriyoshi Shibata
- 👤 Takayoshi Shimizu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:59
CPC Classifications
C; C21; C21D; C21D9/00; C21D9/0068; C22; C22C; C22C38/00; C22C38/18; C22C38/40; C22C38/44
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
123 words
A massive martensite steel for a mold for plastic molding consisting of up to 0.05% carbon, up to 1.0% silicon, up to 2.0% manganese, 5.0-8.0% nickel, 11.0-15.0% chromium, 1.0-4.0% molybdenum, 0.5-4.0% copper, 0.5-2.0% cobalt, at least one machinability-improving component selected from the group consisting of 0.03-0.30% lead, 0.01-0.20% tellurium, 0.002-0.020% calcium, and 0.03-0.40% bismuth, at least one toughness and hardenability-improving component selected from the group consisting of up to 3.0% tungsten, up to 0.01% boron, up to 0.5% titanium, up to 0.5% vanadium, up to 0.5% niobium, and up to 0.5% tantalum, and the balance iron and inevitable impurities, which exhibits a hardness of H R C 30 or higher after age-hardening treatment at 450°-550° C. and resistance to corrosion by halogen gas.
Claim 2
Dependent Claim
123 words
A massive martensite steel for a mold for plastic molding consisting of up to 0.05% carbon, up to 1.0% silicon, up to 2.0% manganese, 5.0-8.0% nickel, 11.0-15.0% chromium, 1.0-4.0% molybdenum, 0.5-4.0% copper, 0.5-2.0% cobalt, at least one machinability-improving component selected from the group consisting of 0.03-0.30% lead, 0.01-0.20% tellurium, 0.002-0.020% calcium, and 0.03-0.40% bismuth, at least one toughness and hardenability-improving component selected from the group consisting of up to 3.0% tungsten, up to 0.01% boron, up to 0.5% titanium, up to 0.5% vanadium, up to 0.5% niobium, and up to 0.5% tantalum, and the balance iron and inevitable impurities, which exhibits a hardness of H R C 30 or higher after age-hardening treatment at 450°-550° C. and resistance to corrosion by halogen gas.
Claim 3
Dependent Claim
103 words
A massive martensite steel for a mold for plastic molding consisting of up to 0.05% carbon, up to 1.0% silicon, up to 2.0% manganese, 5.0-8.0% nickel, 11.0-15.0% chromium, 1.0-4.0% molybdenum, 0.5-4.0% copper, 0.5-2.0% cobalt, at least one toughness and hardenability-improving component selected from the group consisting of up to 3.0% tungsten, up to 0.01% boron, up to 0.5% titanium, up to 0.5% vanadium, up to 0.5% niobium, and up to 0.5% tantalum, and the balance iron and inevitable impurities, which exhibits a hardness of H R C 30 or higher after age-hardening treatment at 450°-550° C. and resistance to corrosion by halogen gas.
Claim 4
Dependent Claim
103 words
A massive martensite steel for a mold for plastic molding consisting of up to 0.05% carbon, up to 1.0% silicon, up to 2.0% manganese, 5.0-8.0% nickel, 11.0-15.0% chromium, 1.0-4.0% molybdenum, 0.5-4.0% copper, 0.5-2.0% cobalt, at least one toughness and hardenability-improving component selected from the group consisting of up to 3.0% tungsten, up to 0.01% boron, up to 0.5% titanium, up to 0.5% vanadium, up to 0.5% niobium, and up to 0.5% tantalum, and the balance iron and inevitable impurities, which exhibits a hardness of H R C 30 or higher after age-hardening treatment at 450°-550° C. and resistance to corrosion by halogen gas.
Claim 5
Dependent Claim
85 words
A massive martensite steel for a mold for plastic molding consisting of up to 0.05% carbon, up to 1.0% silicon, up to 2.0% manganese, 5.0-8.0% nickel, 11.0-15.0% chromium, 1.0-4.0% molybdenum, 0.5-4.0% copper, 0.5-2.0% cobalt, at least one machinability-improving component selected from the group consisting of 0.03-0.30% lead, 0.01-0.20% tellurium 0.002-0.020% calcium, and 0.03-0.40% bismuth, and the balance iron and inevitable impurities, which exhibits a hardness of H R C 30 or higher after age-hardening treatment at 450°-550° C. and resistance to corrosion by halogen gas.
Claim 6
Dependent Claim
85 words
A massive martensite steel for a mold for plastic molding consisting of up to 0.05% carbon, up to 1.0% silicon, up to 2.0% manganese, 5.0-8.0% nickel, 11.0-15.0% chromium, 1.0-4.0% molybdenum, 0.5-4.0% copper, 0.5-2.0% cobalt, at least one machinability-improving component selected from the group consisting of 0.03-0.30% lead, 0.01-0.20% tellurium 0.002-0.020% calcium, and 0.03-0.40% bismuth, and the balance iron and inevitable impurities, which exhibits a hardness of H R C 30 or higher after age-hardening treatment at 450°-550° C. and resistance to corrosion by halogen gas.
Claim 7
Dependent Claim
65 words
A massive martensite steel for a mold for plastic molding consisting of up to 0.05% carbon, up to 1.0% silicon, up to 2.0% manganese, 5.0-8.0% nickel, 11.0-15.0% chromium, 1.0-4.0% molybdenum, 0.5-4.0% copper, 0.5-2.0% cobalt and the balance iron and inevitable impurities, which exhibits a hardness of H R C 30 or higher after age-hardening treatment at 450°-550° C. and resistance to corrosion by halogen gas.
Claim 8
Dependent Claim
65 words
A massive martensite steel for a mold for plastic molding consisting of up to 0.05% carbon, up to 1.0% silicon, up to 2.0% manganese, 5.0-8.0% nickel, 11.0-15.0% chromium, 1.0-4.0% molybdenum, 0.5-4.0% copper, 0.5-2.0% cobalt and the balance iron and inevitable impurities, which exhibits a hardness of H R C 30 or higher after age-hardening treatment at 450°-550° C. and resistance to corrosion by halogen gas.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-14 | 1984-04-14 | 1984-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-14 | 1988-04-14 | 1988-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-14 | 1992-04-14 | 1992-10-14 | $7700.00 | Window Closed / Lapsed |