DE635220C - Process for preparing metal workpieces for mechanical processing to be carried out in stages - Google Patents

Description

Process for preparing metal workpieces for one in stages Machining to be performed There is already a method of preparation of metal workpieces for mechanical processing to be carried out in stages, such as drawing, rolling or deep drawing, with the saving of intermediate anneals between the processing stages have been proposed in which on the cleaned workpiece a thin coating made of a softer metal (alloy) is applied. the The surface of the workpiece, which has already been cleaned by the usual pickling, is thereby before applying the coating by a special etching agent or mechanically roughened. Now there are products made of iron or steel or other metals low stretchability, which, as they depend on their shape and dimensions the starting workpieces differ relatively little, only in a few work stages to be obtained from the original piece. This is e.g. B. in boiling tubes of Locomotive boilers the case when certain measures are taken in three to four Drawing steps from the starting pipe section in the desired cross-sectional and length dimensions be won. But it should also be possible to do it in one or two stages to obtain. That would also be straightforward per se using the above-mentioned method can be achieved by cold means without any intermediate annealing being necessary would be. However, there is the disadvantage that the coating made of lead, lead alloys O. The like. Is not consumed in these few processing stages, so that a A considerable part of the applied lead or the like is lost and also after Completion of the work stages in particularly expensive and cumbersome work processes must be removed. For this reason, the above method is for machining of workpieces not applicable in a few work stages.

It is known to work pieces with a fatty, non-metallic To provide coating. With such a coating one could, if the drawing stages were proportionate were small, make two to three moves without renewing the cover.

According to the invention, the workpieces are in the usual way Pickling cleaned and also by a special etching bath or on a mechanical one Ways are roughened, -and on the workpieces treated in this way, a greasy, solidifying one becomes and a solidifying coating of greasy or other non-metallic lubricants upset. All non-metallic substances can be used as such lubricants in question, which reduce the frictional resistance and z. B. Talc, feather white, soapstone, Graphite or black lead, individually or in mixtures, or consist of these.

Through the joint application of a special conscious roughening by an etching agent or by mechanical means in addition to the usual cleaning of the Workpieces through Pickling in connection with a grease coating the mentioned substances is made possible,. to use much coarser work stages, than it was previously possible, -if you put a fat coating on by a pickling bath only cleaned work pieces. -, Shall z. B = steel pipes in about three to four steps are drawn, a bath of the following composition can be used: It is a mixture by weight of about 2/3 linseed oil and 1/3 turpentine 1/3 of the total weight of this mixture was added black lead (lead oxide) and that Whole intimately mixed. The starting workpieces are immersed in this bath and short Time left in it. After dipping, the workpieces are allowed to dry, which is approximately 1/4 hour time required; the workpieces then have a solidified surface on their surface thin coating, which allows the workpieces as they are, in the cold way -and: without any intermediate treatment, add three to four roughly graduated drawing cycles subject. In the case of tubular workpieces, the bath liquid also penetrates inside of the workpiece and also forms a coating inside, which causes the drawn tubes become perfectly smooth inside.

It was like that B. possible, steel pipes of 56 mm inside width and one Wall thickness of q. mm in four steps. to 25 mm clear width and 1.8 mm wall thickness to pull on the cold route without intermediate treatments.

But if you want z. B. a tube of 38 mm clear width and q. Draw mm wall thickness in two working stages onto a tube of 26 mm inside width and 2 mm wall thickness, see above. it is recommended; use a bath of the following composition: 58 parts by weight of water, 10 parts by weight of soap, 2 parts by weight of castor oil, 15 parts by weight of wool fat and 15 parts by weight of feather white. In order to obtain the most even bath possible, this mixture is heated to 7o to 8o ° C. The workpieces are immersed in this bath for about 2 to 3 minutes; after excavation they are left to dry, which takes about 1/4 hour. It @ Ii'1 @ r @ et gave way here, too, to a solidified coating which enables cold drawing in 1 to 2 stages.

Of course, the baths listed here as examples both their composition and their proportions can be changed. The only important thing is that these baths contain substances which, after the solidification of the The layer taken away from the workpieces from the bath, a more or less firm one Form coating, which is partly in the depressions and canals of the roughened Metal surface has penetrated and in this way the coating on the surface anchored in such a way that it is not immediately stripped off by the tools. It recommends not to start processing earlier than determined is that the coating is completely solidified and dry. This can also be done by Heating the coated workpieces can be accelerated.

Claims (1)

PATENT CLAIM: Process for preparing metal workpieces for mechanical processing to be carried out in stages, such as drawing, rolling or deep drawing, in order to save intermediate annealing between the processing stages, whereby on the through a pickling bath cleaned workpiece a thin coating of a lubricant is applied is characterized in that it is cleaned by a conventional pickling bath and also surface roughened by an etching bath or by mechanical means of the workpiece a solidifying and solidifying coating of greasy or other non-metallic lubricants is applied.