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).
Material specification for Chrome Vanadium Steel Spring Wire.
| Identifier | ExFiles\Box 17\6\ Scan220 | |
| Date | 9th May 1934 guessed | |
| CADILLAC MOTOR CAR COMPANY INTER-ORGANIZATION LETTERS ONLY TO ADDRESS FROM ADDRESS DATE SUBJECT Chrome Vanadium Steel Spring Wire - G.M. 62-M Handwritten: Cad 65 actually used General: This specification covers wire for highly stressed springs. It shall be uniform in quality and shall not be wavy or crooked. The steel shall be made according to approved practice by the electric furnace process and shall conform in composition to G.M. X6150. Chemical composition in percentage of G.M. X6150: Carbon................... 0.45-0.55 Manganese................ 0.60-0.80 Phosphorus............... 0.025 Max Sulphur.................. 0.025 Max Silicon.................. 0.15-0.30 Chromium................. 0.80-1.10 Vanadium................. 0.15 Min Surface and Cleanliness: The surface shall be smooth and bright with at least one pass through the dies after the last anneal. It shall be free from 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. Physical Properties: Tensile strength shall not be less than 100,000 lbs. per sq. in. Heat Treatment: Springs coiled from this wire shall be hardened and tempered. Suggested heat treatment: Heat to 1625°F.{Mr Friese} Quench in oil. Temper at 780°F for 30 minutes. Cool in air. Straighten. Retemper at 700°F for 30 minutes. Cool in air. Physical Properties after Heat Treatment: 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. Rockwell Hardness C-47 to C-51 Notes: Wire made to this specification is suitable for rapidly or highly stressed helical springs such as valve springs. Handwritten (left margin): ? JHS Top Left Corner: CM 47 J | ||