BS EN 657-2005 pdf download.Thermal spraying Terminology ,classification.
This BS EN 657 defines processes and general terms for thermal spraying. It classifies thermal spraying processes according to type of spray material, to type of operation and to type of energy carrier.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
EN ISO 14923, Thermal spraying — Characterization and testing of thermal sprayed coatings (iSO 14923:2003)
EN ISO 17836, Thermal spraying — Determination of the deposition efficiency for thermal spraying (ISO 17836:2004)
3 Terms and definitions
For the purposes of this document, the following term and definition applies.
thermal spraying (TS)
process in which surfacing materials are heated to the plastic or molten state, inside or outside of the spraying gun/torch, and then propelled on to a prepared surface; the substrate remains unmelted
NOTE To obtain specific properties of the deposit, a subsequent thermal, mechanical or sealing treatment may be used.
4 Process variations
4.1 Classffication according to the type of spray material Distinction of the following variations:
wire spraying:
— rod spraying:
-— cord spraying;
— powder spraying;
6.1.2 Sprayability
The sprayability is a property of the spray material. It is influenced by:
— chemical composition and physical properties;
— manufacturing process of the spray material e.g. as a wire, rod, cord or powder;
— morphology, particle size range and its distribution in case of powders:
flowability of powders;
feeding behaviour of wires, rods and cords.
Coating structure and build up of coating will be influenced by sprayability.
6.1.3 Coating functionality
The coating functionality is a property of design. The coating can function if the component is coated with a suitable spray material and applied on a suitable substrate material. Thus the coating is working satisfactorily under the stipulated service conditions.
Coating functionality is influenced by:
— state of design (location of surface to be coated, avoiding edge pressing and sharp edges and narrow radii to be coated, thickness of coating and substrate);
stresses between coating and substrate (avoiding higher tensile or compressive stresses ri the coating and differences in expansion coefficient);
— temperature, temperature cycling, and risk of parent metal corrosion.
The general production ability of the component together with its particular influencing factors substrate material, design and manufacturing have to be determined independently from the coating feasibility.
6.1,4 Coating quality
Coating quality is a manufacturing property. Adequate quality can be achieved if, the thermally sprayed coating envisaged for a particular component can be made properly under the chosen manufacturing conditions and by applying a suitable spray material.
The coating quality is influenced by the following factors:
— surface preparation prior to spraying;
6.1.5 Accompanying specimen
The accompanying specimen has to be coated under conditions as similar as possible to that of
manufacturing.
6.2 Thermal spraying equipment terms
6.2.1 Spray gun
Unit with which the spray material is heated to the plastic or molten state, accelerated and projected on to the prepared substrate surface.
6.2.2 Spray nozzle
The spray nozzle is that part of the spray gun, which contains the outlet opening for the spray stream.
6.2.3 Supplementary nozzle
Supplementary nozzles are spray nozzles that influence directly shape, configuration and direction of the spray stream. They can be applied for cooling purposes also.
6.2.4 Contact tube
The contact tube is an electrically conductive part (electrical conduit) of the nozzle system of an arc spray gun to which wires are guided along electrical contacts toward a point of intersection, and shortcircuiting, at a desired angle.
6.2.5 Wire feed mechanIsm
The wire feed mechanism is a mechanically operated unit for a controlled delivery of the spray material in the
form of wire, rod or cord.
6.2.6 Powder feeder
Powder feeding units are systems for a controlled supply of spray material in the form of powder.
6.2.7 Powder Injector
Powder injectors feed and guide spray powders into the gas stream. They may be integrated in the spray gun
or mounted outside of it.
6.3 Process-specific terms of thermal spraying
6.3.1 Spray material.BS EN 657-2005 pdf download.