ISO 14231:2000 pdf download
ISO 14231:2000 pdf download.Thermal spraying -Acceptance inspection of thermal spraying equipment.
c) the selected parameters shall be constant and reproducible, preconditions being that carrier gas pressure or actuating air pressure, and supply of electrical power be maintained at constant and controllable levels.
6.3.4 Monitoring
Any deviations from the selected parameters, gas pressure and gas volume flow rate, that occur during the spraying process shall be capable of being monitored and controlled by means of appropriate instruments that can be read clearly and correctly. The limits of error of the instruments shall not exceed 5 % for all selected parameters. The maximum permissible error for pressure gauges and electrical measuring instruments shall be 2,5 % of the measuring span or scale (see also 7.4.5).
7 Acceptance inspection procedure
7.1 General
Spraying equipment shall be deemed to be adequately designed for all relevant spraying applications and for use with all customary spraying materials if it complies with the requirements given in 7.2 to 7.4.
7.2 Plasma spraying equipment
7.2.1 Electrical power
Proof of the power rating shall be given by spraying aluminium oxide for 20 mm using the parameters recommended by the equipment manufacturer.
During the test the following items shall be examined:
a) gas control;
b) electrical control;
c) cooling temperature.
The percentage limitations for selected parameters are given in annex A, classes A, B and C.
Upon stabilization, the deviation of the voltage (a variable parameter) from the selected value shall not exceed 3 % for class A, 6 % for class B and 12 % for class C. The time for the voltage to stabilize shall be recorded.
7.2.2 High voltage ignition devices
The high voltage ignition device shall be deemed to meet the requirements given in 6.1 .2 if it does not interfere with
any appliances and functions of the spraying equipment during the test specified in 7.2.1.
7.2.3 Cooling water circuit
The cooling water circuit shall be tested by measuring its capacity. The minimum volume flow rate, as specified by the manufacturer, shall be confirmed.
7.2.4 Plasma gases
The system shall be deemed to comply with the requirements specified in 6.1.4 if the values of the gas pressure and gas volume flow rate do not deviate from the selected parameters by more than ± 1,5 % for class A, ± 3 % for class B and ± 5 % for class C during a 20 mm period of spraying.
If the secondary gas is the variable parameter, the deviations from the selected value, after stabilization, shall not exceed 3 % for class A, 6 % for class B and 12 % for class C.
7.2.5 Nozzle
The nozzle is deemed to comply with the requirements of 6.1.5 if no deposits interfere with the spraying operation
specified in 7.2.1.
7.2.6 Powder feed unit
Compliance with the requirements specified in 6.1 .6 shall be tested as follows:
a) A change in the primary gas flow, as indicated on the control panel, shall not affect the carrier gas flow.
b) To determine the mass of powder fed over a given period, the system shall be operated in the “cold run” mode, i.e., with the arc not operated for at least 1 mm. During this process, which is to be repeated twice more, the variation in the mass of powder fed shall not exceed ± 5 % for class A, ± 10 % for class B and ± 15 % for class
C. The particle size of the test powder shall be selected by agreement between the parties concerned (see ISO 14232). To check reproducibility, the same feed rates and the same deviations shall be achieved after shut-down of the equipment for at least 6 h and after recharging with the same type and amount of powder.
c) This test shall be conducted with a powder in accordance with ISO 14232 selected by agreement between the parties concerned. A sample of 6,4 kg is taken from a well-mixed powder and split into four equal parts. The procedure for mixing and splitting of each quarter is repeated until a sample of 100 g is obtained. This sample shall be analysed chemically and its particle size determined before feeding. The powder container shall then be filled with 1 000 g of the spraying powder. After feeding through about 900 g with the equipment in the “cold-run” mode, in accordance with the manufacturer’s operating instructions, the remaining quantity of about 10 % shall be analysed chemically and its particle size determined. The chemical analysis may be limited to the determination of the principal constituent. The deviation caused by de-mixing of the powder shall not exceed 3 % of the initial values.
7.2.7 Monitoring
The limits of error of the measuring instruments and control units shall not exceed 5 % for all selected parameters and the maximum permissible error shall be 2,5 % of the measuring span or scale. The reproducibility of the setting shall be demonstrated.
7.2.8 Inspection report
An example of an inspection report for plasma spraying equipment is given in annex A.
