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 applying Stellite to valve steel using an acetylene torch.
| Identifier | ExFiles\Box 158\4\ scan0173 | |
| Date | 20th September 1937 guessed | |
| -2- A 3 - 5 lbs/sq.in. pressure of acetylene and 10 - 15 lbs/sq.in. pressure of oxygen is recommended. The purity of acetylene cannot be over emphasised, as impurities give rise to inclusions in the deposit. Dissolved acetylene in bottle form is the purest. The flame is so regulated that the cone of flame when applied to the molten metal does not tend to blow or penetrate it, but merely causes a pool of molten metal to spread. The blowpipe should be held close enough to the work so that the inner neutral cone of the flame is not more than 1/8" from the surface. (5) All particles of scale and oxide should be floated to the surface since they will cause holes if left in the metal. Another cause of pin holes in the finished surface is an insufficient supply of acetylene which should produce a flame as shown in our sketch when correct. Likewise trouble occurs if the welding rod of Stellite is applied before the base metal has reached the sweating surface heat, also the removal of the welding flame from a pool of Stellite should not be sudden. (6) Before applying the Stellite, the valve steel should be heated until 'sweating' is observed i.e. when the steel is heated to the point where Stellite will wet the surface and flow readily immediately it is applied. It will be seen that whilst the steel is not molten it has a glistening appearance when observed through the welding goggles and is what we define as sweating. Emphasis should be made, avoiding overheating of the steel and the lowest temperature at which the Stellite will wet the steel gives the best results. (7) The valve should be mounted at an angle of approximately 30° to the vertical and stand on a solid copper block. Whilst the Stellite is being applied the valve should have a rotary motion of 1 rev. in 2 minutes and have 5 revs. in completing the Stelliting. Once the operation of Stelliting has been started it should be continuous likewise the rotation of the valve at the above speed. continued | ||