From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Specification for soft Swedish steel valve spring wire.
| Identifier | ExFiles\Box 17\6\ Scan221 | |
| Date | 17th May 1934 guessed | |
| GM 47 J CADILLAC MOTOR CAR COMPANY INTER-ORGANIZATION LETTERS ONLY TO DATE ADDRESS FROM ADDRESS SUBJECT Soft Swedish Steel Spring Wire - G.M. 64-M General: This specification covers an excellent grade of valve spring wire uniform in quality and temper. It shall not be wavy or crooked. The steel shall be made according to approved practice by the electric furnace or acid open hearth process and shall conform in composition to G.M. X1065. Chemical Composition in Percentage of G.M. X1065: Carbon......................... .60-.70 Manganese...................... .60-.80 Phosphorus..................... .025 Max Sulphur........................ .025 Max Carbon and Manganese may be varied by the manufacturer at his discretion providing the physical properties specified for the finished and heat treated spring are obtainable and providing purchaser does not specifically stipulate otherwise. Surface and Cleanliness: The surface shall be free from rust, scale, scratches and die marks. Samples from any bundle when etched in hot hydrochloric acid solution sufficiently to disclose surface defects, shall show no hair line seams, pits, gouges, cracks or other imperfections. The number and size of non-metallic inclusions of any type shall not be greater than shown in Class A, Non-Metallic Inclusion Chart, published in G.M. Standards. Heat Treatment: Springs coiled from this wire shall be hardened and tempered. Suggested heat treatment after forming: Heat to 1500°F.{Mr Friese} Quench in oil. Temper at 680°F for one hour. Cool in air. Straighten. Retemper at 600°F for 30 minutes. Cool in air. Physical Properties after Heat Treatment: This material shall, after suitable heat treatment, meet all the physical property requirements specified for Oil Tempered Swedish Spring Steel Wire G.M. 63-M.{Mr Moon / Mr Moore} Valve Springs or other springs subjected in use to considerable vibration shall, on requirement meet the following fatigue test: Springs shall withstand 9 hours continuous running at period of greatest vibration or noise, without breakage or set of more than 2% of original weight at position of greatest load when assembled. Hardness (Rockwell)......................... C-47 to C-51. Handwritten text: Top Right: Card 83 Actually need Left Margin: Cad. Valve Springs Stress Range 38,000 to 79,000 | ||