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).
Instructions for the production and forging of experimental valves using 'Staybrite' material.
| Identifier | ExFiles\Box 154a\1\ scan0052 | |
| Date | 30th June 1926 | |
| X4111 HS.{Lord Ernest Hives - Chair} RHC.{R. H. Coverley - Production Engineer} Mr.Probert. Mr.Shelton. Cr{Mr Cra???ster / Mr Chichester} no.Pendlebury. Mr.Marriott will hand over to you two pieces of "Staybrite" material for the production of a certain number of experimental valves. What I wish you to produce at the moment is two sets of Phantom and two sets of 20 HP. valves, with two spares for each. The material can be forged by any of the ordinary processes, it not being necessary to take the special precautions which are called for with our S.L.V. steel. The minimum temperature below which no forging should be done on them is 1000°C. If forging work is carried out below this temperature, there will be a tendency to red shortness, owing to the fact that the steel definitely hardens under cold working conditions. The expansion of "Staybrite" is about 50% greater than mild steel, and allowance should be made in forging to cover this increased contraction. The valves in question will be forged against an experimental number, which will be given you by Mr.Shelton. To thoroughly soften the valve forgings for machining purposes, they must be heated up to 1200°C and cooled out in air. If they appear then to be still somewhat difficult to machine, we should try a similar temperature but cool out by quenching in water. I do not wish to go to this latter process unless it proves necessary during the machining operation. The upper forging limit should correspond with that for stainless steel(the actual temperatures being 1250 to 1300°C) The hot work should be performed quickly, that is, rapid forging should take place at high temperatures, and it is most important that no work should be done on the material after it drops below 1000°C. This material could be worked on the Ryder Hammer if the above instructions are worked to, but there is always a temptation on the Ryder to continue Con. | ||