ISO 14920 pdf download

ISO 14920 pdf download.Thermal spraying — Spraying and fusing of self-fluxing alloys 1 Scope This standard covers thermal spraying of self fluxing alloys that are simultaneously or subsequently fused to create a homogeneous, diffusion bonded coating. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text, and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies. 3 Design considerations To ascertain whether sprayed and fused alloy coatings are suitable for the intended engineering application, consideration shall be given to the factors in the following sub-clauses. 3.1 Substrate (base metal) 3.1.1 As the process requires the application of heat to fuse the coating to the substrate, consideration shall be given to the possible effects of such heating on the substrate, including: a) distortion; b) scaling; c) the need to stress relieve; d) an irreversible transformation of the mechanical and/or metallurgical properties. Martensitic steels are susceptible to stress cracking and alloys containing significant amounts of C, Al, Ti, Mg, S, sulfides, P, and Nitrogen can create porosity in the coating and may render the substrate liable to stress cracking. 3.1.2 The preparation of the component for a sprayed and fused coating usually includes a reduction of the design dimensions. Consideration shall be given to the effect of such reduction on the required physical properties and the fact that the resultant sprayed and fused coating may have differing physical properties. 3.1.3 The fatigue strength, shock resistance and other properties of the component may be affected by the application of the coating. 4 Self-fluxing alloy selection 4.1 Choice The choice of coating alloy will determine the properties of the final deposit. e.g. a) hardness; b) resistance to wear and corrosion; c) machinability; d) suitability for the application.4.2 Composition The composition of the coating will determine the properties of the final deposit. Consideration shall be given to the effects of the stresses anticipated in service. Substrate alloys which are subject to a martensitic change require a coating alloy with a high ductility. Consideration should also be given to the need for post heat treatment. Guide to approximate hardness of the fused deposit...