The purpose of this Defence Standard is to provide designers and
users with advice on the application of flame sprayed coatings,
principally for wearing surfaces. It includes cleaning, preparation
of surfaces, design considerations, metals to be applied, quality
control, inspection, and testing.
It is not intended to apply to aerospace parts and
This Defence Standard is divided into three parts:
Part 1, Unfused metal coatings
Part 2, Fused metal coatings
Part 3, Ceramic and cermet coatings.
Part 2, Fused metal coatings, covers the use and application of
flame sprayed and subsequently fused coatings. These are applied to
selected areas of engineering components to provide resistance to
wear, abrasion, erosion, galling, and fretting, and to confer
oxidation and corrosion resistance, particularly where these
destructive influences accentuate wear. These coatings are used
either to build up or repair components showing rapid destructive
attack in service, or to provide specific desired service
characteristics to new components by incorporating such coatings in
the initial design, and applying them during manufacture.
By way of example, the following are typical applications:
(1) The sliding wear and hence dimensional variation of plug,
ring, and snap gauges is minimized by coatings of fused
nickel-chromium-boron alloys incorporating tungsten-carbide
particles. Similar coatings are used to reduce the wear on press
(2) Plug valves of cast iron and stainless steel handling
abrasive and corrosive fluids under high pressure are subject to
galling, abrasion, and corrosion. These can be overcome by
hard-facing with fused coatings of nickel-chromim-boron alloys.
Pump sleeves, shafts, and plungers can be similarly protected.
(3) Refinery hot oil gumps, sleeves, and shafts operating at
high temperatures (345ºC) and high pressure (24.0 - 34.5 bar -/)
and handling fluid-borne abrasive particles are protected against
abrasive wear at high temperatures by
cobalt-chromium-tungsten-boron alloys incorporating tungsten
(4) The heads of diesel engine pistons are protected against
high temperature corrosion caused by diesel oil combustion residues
by a fused nickel-chromium-boron coating.
Note: -/ 1 bar = 105 N/m2.
(5) To resist severe abrasive wear in bridge and core mandrels
of brick making extruders, these are hard-faced by fused coatings
of nickel-chromium-boron alloys. Shafts of cement mixers and
conveyor screws are similariy treated.
(6) To resist high temperature oxidation, which discolours
glassware, and to prevent wear of cast iron plungers in glass press
and blow manufacture, the plungers are protected by fused
machineable coatings of nickel-chromium-boron alloys.
This Standard must not be taken as approval to apply any flame
sprayed coating to a component without the written consent of the
purchaser or owner. This written consent may be in the form of a
contract or order, or may be in the from of written permission from
the Design/Approval Authority concerned.
If this Standard should be found unsuitable for a particular
requirement, the Directos of Standardization shall be informed of