The founder's manual; a presentation of modern foundry operations, for the use of foundrymen, foremen, students and others

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1917 Excerpt: ...been blowing iron, analyzing from 0.90 to 1.25 per cent silicon from the cupola, and often has been obliged to use scrap while blowing. There is an advantage in the increased amount of scrap which can be carried, as it cuts down the cupola loss by increasing the amount of carbon in the charge. For example: He charges 50 per cent pig carrying about 3.75 per cent carbon and 50 per cent scrap having 0.25 per cent carbon. Tests from such iron from the cupola give 3.25 to 3.50 per cent carbon, showing a gain of 1.25 to 1.50 per cent carbon, taken from the coke, instead of purchased in the pig iron. 50 per cent scrap can be melted in the cupola, using only I2H per cent coke, but the blower must have a complete knowledge of cupola practice. Most blowers use too much volume and too high pressure of blast to get the best results. With low silicon the volume and pressure of blast must be low. No two blows will act alike and require different treatment, which can be determined by the flame, but which he is unable to describe. It is as necessary for the blower to regulate the air valve to get proper combustion as it is for the melter to adjust air and gas valves. With ordinary care the steel produced in a converter is very uniform in carbon and silicon; more so, he thinks, than in the open hearth. The greatest variation seems to be in manganese. The temperature of the metal and the condition of the slag cause more variation in the converter than in the acid open hearth. It is possible to run several weeks without taking an analysis and find at the end of the run very little variation in the elements. While this is possible with the open hearth, it is not practiced on account of the risk. It is, however, frequently done in converter practice. The method of making the mo...