GB626604A - Improvements relating to controlling the composition of steel alloys during the manufacture thereof - Google Patents

Abstract

626,604. Alloys. STEVENS, A. H. (Bransome, E. D.). Dec. 30, 1942, No. 9625/44. Divided out of 608,486. [Class 82(i)] A process controlling the composition of steel alloys, during the manufacture thereof, comprises testing a sample obtained from a bath of the same to determine the actual nitrogen content relative to a standard of known low active nitrogen content, the standard having known physical properties and substantially the same chemical composition as the sample except for active nitrogen, and adding to the bath of steel alloy a nitrogendeactivating material in an amount in accordance with the test sufficient to produce a steel alloy having desired physical properties with respect to the physical properties of the standard. The test consists in casting a block 61 from a sample of the steel bath, and inserting the block and a standard block 60 in a furnace 62, a pyrometer being connected to each block in such manner that any difference in temperature between the sample and standard may be recorded. In Fig. 1, the hot junction 64 of a thermocouple is placed in the standard and the cold junction 65 in the sample, and readings are taken on a recording instrument 63. A second thermocouple 69 connected to an indicating device 70 shows the actual temperature of the furnace. The temperature of the furnace is raised to some selected temperature above the critical point of the standard and sample, and the blocks are allowed to cool. Differences in temperature between the standard and sample when they pass through the critical ranges are noted and these differences are used to determine the amount of nitrogen-deactivating material which needs to be added to the steel. The deactivating material employed may be that described in Specification 608,486. A deactivating alloy containing titanium 20 per cent, aluminium 20 per cent, zirconium 7.5 per cent and the balance iron is referred to.