US3847678A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Helical steel spring and method
Assignee: Bethlehem Steel Corp
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Filing: 1972-11-16
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Granted: 1974-11-12
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Expires: 1992-11-16
Abstract
Abstract This invention relates to a quenched and tempered ferrous alloy suitable for helical springs, such as used in automotive suspension systems. More particularly, it is directed to a hotformed, oil-quenched and tempered helical spring formed of a ferrous alloy consisting essentially of, by weight, about 0.51 to 0.91 percent carbon, about 0.75 to 1.00 percent manganese, about 0.70 to 1.10 percent silicon, about 0.25 to 0.40 percent chromium, the remainder substantially iron and incidental impurities. In the formed and heat-treated condition, said springs are characterized by good resistance to load loss, good resilience, resistance to atmospheric corrosion, and good surface qualilty.
Inventors
- 👤 S Furr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:22
CPC Classifications
F; F16; F16F; F16F1/00; F16F1/02; F16F1/021; C; C21; C21D; C21D9/00; C21D9/02; F16F1/04
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
77 words
A QUENCHED AND TEMPERED HELICAL SPRING, HOT-FROMED FROM AS-ROLLED BAR STOCK, CHARACTERIZED BY A HARDNESS BETWEEN ABOUT RC48 AND RE52 AND A HIGH RESISTANCE TO LOAD LOSS AS EXEMPLIFIED BY A BAUSCHINGER TWIST/PERMANENT SET RATIO BETWEEN ABOUT 0.85 AND 1.10, AND CONSISTING ESSENTIALLY OF, BY WEIGHT, ABOUT 0.76 TO 0.91 PERCENT CARBON, ABOUT .75 TO 1.00 PERCENT MANGANESE, ABOUT 0.70 TO 1.10 PERCENT SILICON, ABOUT 0.25 TO 0.40 PERCENT CHROMIUM, WITH THE BALANCE IRON AND INCIDENTAL IMPURITIES.
Claim 2
Dependent Claim
77 words
A QUENCHED AND TEMPERED HELICAL SPRING, HOT-FROMED FROM AS-ROLLED BAR STOCK, CHARACTERIZED BY A HARDNESS BETWEEN ABOUT RC48 AND RE52 AND A HIGH RESISTANCE TO LOAD LOSS AS EXEMPLIFIED BY A BAUSCHINGER TWIST/PERMANENT SET RATIO BETWEEN ABOUT 0.85 AND 1.10, AND CONSISTING ESSENTIALLY OF, BY WEIGHT, ABOUT 0.76 TO 0.91 PERCENT CARBON, ABOUT .75 TO 1.00 PERCENT MANGANESE, ABOUT 0.70 TO 1.10 PERCENT SILICON, ABOUT 0.25 TO 0.40 PERCENT CHROMIUM, WITH THE BALANCE IRON AND INCIDENTAL IMPURITIES.
Claim 3
Dependent Claim
119 words
In a method for producing a helical steel spring for use in automotive suspension systems wherein a steel is melted, cast, solidified, hot-rolled into bar stock, hot-formed in as-rolled condition into said helical steel spring and heat treated to a hardness range of Rc48 to Rc52, the improvement comprising in combination therewith the steps of hot-forming a steel consisting essentially of, by weight, about 0.76 to 0.91 percent carbon, about 0.75 to 1.00 percent manganese, about 0.70 to 1.10 percent silicon, about 0.25 to 0.40 percent chromium, remainder iron and incidental impurities, wherein said helical steel spring is characterized by a high resistance to load loss as exemplified by a BaUschinger Twist/Permanent Set Ratio between about 0.85 and 1.10.
Claim 4
Dependent Claim
119 words
In a method for producing a helical steel spring for use in automotive suspension systems wherein a steel is melted, cast, solidified, hot-rolled into bar stock, hot-formed in as-rolled condition into said helical steel spring and heat treated to a hardness range of Rc48 to Rc52, the improvement comprising in combination therewith the steps of hot-forming a steel consisting essentially of, by weight, about 0.76 to 0.91 percent carbon, about 0.75 to 1.00 percent manganese, about 0.70 to 1.10 percent silicon, about 0.25 to 0.40 percent chromium, remainder iron and incidental impurities, wherein said helical steel spring is characterized by a high resistance to load loss as exemplified by a BaUschinger Twist/Permanent Set Ratio between about 0.85 and 1.10.
References Cited (Backward Citations)
US2028029A
Cited
US1972524A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |