1. Field of the Invention
This invention pertains particularly to a drawing mixture which is suitable for rigorous utilizations involving maximum reductions and pass speeds, and also to an improved drawing procedure and utilization of drawing lubricants. A phase of the invention deals with a dry lubricating type of drawing mixture that has a proportioned content in a mixed relation and whose ingredients serve in a complementary highly improved manner to protect the surface of a metal workpiece being drawn under strenuous conditions.
2. Description of the Prior Art
Various types of dry and wet lubricating compounds and mixtures have been used in the drawing of metal workpieces, such as steel, and in drawing high carbon and specialty steel material into wire or rod lengths. There has been a somewhat general adoption of a method which involves the application of a dip-applied lead coating to the workpiece to which is applied ordinary soap powder at the entrance to each draw die. In this connection, a cleaned rod, for example, is dipped to provide the lead coating and is then passed through a requisite number of dies to produce the desired final or semi-final product. In utilizing such a coating, it is important to control the speed so as to prevent a rise of temperature to near the melting point of the coating which in the case of lead is around 621.degree. F. Also, as the drawing progresses, the coating tends to become thinner and less effective thus limiting the percentage of reduction during continuation of the operation. For a less stringent type of operation, where the workpiece is not quite so hard or brittle a material, a modified form of coating is provided which utilizes an acid salt and may include a drawing compound in the nature of a sodium resin silicate.
It has been my experience that the present types of drawing or lubricating methods have all been of a production limiting nature, and although rejects have been reduced from about 50% to possibly 30% at the present time, the percentage is so great as to make the resultant product relatively expensive. Also, restrictions on the speed of operation, as well as the percentage reduction, have been limitations which have increased the cost of a product and made it relatively expensive. Also, restrictions on the speed of operation, as well as the percentage reduction, have been limitations which have increased the cost of a product such as welding rod, rope and bridge wire, music spring and valve spring wire, binding wire, etc.