GB693114A - Parting composition and method of pack-rolling using the same - Google Patents

Abstract

Parting compositions for use in the hot pack-rolling of metal slabs and plates (see Group XXII), comprise a homogeneous suspension of inorganic material which is substantially infusible, inert to the metal to be rolled, and non-decomposable below 2400 DEG F., and which passes a 100 mesh standard A.S.T.M. sieve, in a solution of about 0.04-4 per cent by weight of a cellulose ether or ester in a volatile organic solvent substantially free from chemically combined chlorine and aromatic hydrocarbons, the solvent comprising an ester of a saturated fatty acid containing 1-5 carbon atoms with an aliphatic alcohol containing 1-5 carbon atoms. The proportion of the inorganic material to the solution is between about 3 and about 1/3 volumes of the former per volume of the latter, said volumes being the volumes of the stated components before mixing together and the volume of the inorganic material being measured after pouring the material into a container without tamping or violent tapping. The cellulosic binder may be an ethyl cellulose, particularly of about 47-50 per cent ethoxy content, a cellulose acetate or a p cellulose nitrate, the latter being preferred. The inorganic material may be a refractory metallic oxide such as magnesium, zirconium, aluminium, or titanium oxide, the chromium oxides, such as precipitated chromium sesquioxide, a refractory silicate such as mica or magnesium silicate, chromite or calcined periclase. The solvent may be methyl, ethyl, isopropyl, butyl or amyl acetate, ethyl acetate being preferred. The solvent may comprise a mixture of esters and may contain a minor proportion of another volatile solvent or solvents such as a lower aliphatic alcohol, e.g. methyl, ethyl or propyl alcohol, or a lower aliphatic ketone such as acetone. In an example a cellulose nitrate is dissolved in ethyl acetate to provide a concentration of 0.4 per cent by weight. With this solution is thoroughly mixed an equal volume of chromium sesquioxide passing a 350 A.S.T.M. standard sieve, and the paint-like composition is applied to one face each of stainless steel plates to be pack rolled (see Group XXII). The composition does not deleteriously affect, as by carbonization, the surfaces of the metal members to which it has been applied, dries quickly and does not disintegrate during the process with exposure of the underlying metal surfaces.