All right, I think I have it sorted. Joseph Whitworth patented his compressed fluid steel process in 1865 and the term or protection ran until 1879. At that time after consideration by the powers that be, it was determined to extend the protection period for another 5 years until 1884. Even though the process(not steel type) was patented in 1865, it wasn't fully developed until 1869, a time when the Siemens-Martin furnace came online in Britain by at least 3 makers and was the result of a compromise of between Carl Wilhelm Siemesn & Pierre-Émile Martin. Joseph Whitworth & Company, Limited(converted/formed 1864) owned 2 Siemens-Martin furnaces where they took pig iron and heated it up to a fluid state. It took about 8 hours to complete the cycle and was quite longer than the Bessemer process. But it allowed for better quality control. Can't say if they added any percentages. Anyway, while in a fluid state they formed ingots under pressure and some applications may have been pressed into the desired cast form. Whitworth had corresponding pressure requirements for specific steel needs.
Kind Regards,
Raimey
rse
