US4170495A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and means for hardening and hot-zincing iron and steel products
Assignee: Individual
•
Filing: 1976-06-30
•
Granted: 1979-10-09
•
Expires: 1996-06-30
Abstract
Abstract A method for hot-zincing and hardening iron and steel products. After removing grease from the products they are heated to austenitizing temperature and are subsequently introduced directly into a zinc bath for simultaneous zincing and hardening.
Inventors
- 👤 Raimo Talikka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:20
CPC Classifications
C; C21; C21D; C21D1/00; C21D1/34; C21D1/44; C21D1/48; C21D1/18; C21D1/19; C21D1/20; C23; C23C; C23C2/00; C23C2/003; C23C2/0038; C23C2/02; C23C2/022; C23C2/0224; C23C2/024
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
130 words
A method for simultaneous hardening and hot-zincing of low-carbon steel products consisting of the consecutive continuous steps of heating the products in a furnace to the austenitizing temperature of 850°-1000° C. in an atmosphere of a reducing gas to prevent decarburizing, evening and controlling the temperature of the austenitized products to a temperature not below the A c3 temperature in the end zone of said furnace in an atmosphere of a carbon-free protective gas to protect against contact with oxygen, introducing said products directly into a zinc bath at a temperature above the M s temperature for simultaneous hot-zincing and hardening for a period of time sufficient to produce bainite hardening, removing the hardened zinced products from the zinc bath, removing excess zinc from the products and cooling the products.
Claim 2
Independent Claim
130 words
A method for simultaneous hardening and hot-zincing of low-carbon steel products consisting of the consecutive continuous steps of heating the products in a furnace to the austenitizing temperature of 850°-1000° C. in an atmosphere of a reducing gas to prevent decarburizing, evening and controlling the temperature of the austenitized products to a temperature not below the A c3 temperature in the end zone of said furnace in an atmosphere of a carbon-free protective gas to protect against contact with oxygen, introducing said products directly into a zinc bath at a temperature above the M s temperature for simultaneous hot-zincing and hardening for a period of time sufficient to produce bainite hardening, removing the hardened zinced products from the zinc bath, removing excess zinc from the products and cooling the products.
Claim 3
Dependent Claim
41 words
The method as claimed in claim 1, wherein the reducing gas consists of 20.0% H 2 , 22.5% CO, 1.0% CO 2 and 47.5% N 2 , and the protective gas consists of 75% H 2 and 25% N 2 .
Claim 4
Dependent Claim
28 words
The method as claimed in claim 1, wherein the products to be treated are individually fed in a continuous flow from the heat-treatment furnace into the zinc bath.
Claim 5
Dependent Claim
13 words
The method as claimed in claim 1 wherein the products are hardened screws.
Claim 6
Dependent Claim
18 words
The method as claimed in claim 4 wherein the screws are of the strength classes 8.8 or 10.9.
Claim 7
Dependent Claim
20 words
The method as claimed in claim 1 wherein the temperature of the molten zinc is between 450 and 560° C.
Claim 8
Dependent Claim
31 words
The method of claim 1 wherein the temperature of the zinc is between 450 and 460° C. in a steel container or between 520 to 560° C. in a ceramic container.
Claim 9
Dependent Claim
19 words
The method of claim 1 wherein a minor amount of aluminum or lead is present in the molten zinc.
Claim 10
Dependent Claim
18 words
The method of claim 8 wherein 0.16 to 0.18 percent of aluminum is present in the molten zinc.
References Cited (Backward Citations)
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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) | 1982-10-08 | 1983-04-09 | 1983-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-10-08 | 1987-04-09 | 1987-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-10-08 | 1991-04-09 | 1991-10-09 | $7700.00 | Window Closed / Lapsed |