For climate tests or drying, air-conditioned or heated ambient air is supplied into the test space via the airconditioning unit (incl. refrigeration unit with air-cooled condenser), which is located at the rear. A psychrometric measuring system (dry and wet bulb) with forced wetted wet bulb sensor is installed for measurement and control of humidity.

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Temperature, pressure and humidity are the testing parameters. A parameter is changed for every test. The other two parameters remain unchanged. First of all, every test is performed in a pure synthetic air atmosphere and then in an atmosphere containing a defined quantity of fuel gas. The aim of the test is to discover the effect that a changed parameter has on the signal emitted by the test specimen. Signals and parameters are logged (timedependent), graphically output and stored on data carriers. In addition, any special operating conditions are displayed and logged e.g. exceeding of a threshold value.

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For climate tests or drying, air-conditioned or heated ambient air is supplied into the test space via the airconditioning unit (incl. refrigeration unit with air-cooled condenser), which is located at the rear. A psychrometric measuring system (dry and wet bulb) with forced wetted wet bulb sensor is installed for measurement and control of humidity.

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Thereby, test specimens are exposed to salt spray or condensed water. The system comprises of three major assemblies: test chamber, brine solution storage tank and switch cabinet. A brine solution is sprayed into the test space through nozzles. Depending upon requirements, one, two or more nozzles can be provided. The throughput of one nozzle is approximately 12 litres per day. The brine solution storage tank can hold 600 or 1000 litres. Thus, long term tests lasting for several days are feasible.

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The Brinell hardness test method consists of indenting the test material with a tungsten carbide ball of either 1, 2.5, 5 or 10 mm diameter by applying a test force of between 1 and 3000 kgf. The full load is normally applied for 10 to 15 seconds in the case of iron and steel and for at least 30 seconds in the case of other metals. The diameter of the indentation left in the test material is measured. The Brinell harness number is calculated by dividing the load applied by the surface area of the indentation.

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Type of tests in the metal industry: quasi-static tests, endurance tests, impact tests, fracture mechanics tests, and specimen preparation.

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The portable Sclerograph is based on the dynamic rebound height method. This analog device can be used to determine the hardness of steel and non-ferrous metals. The rebound height is read off and the hardness value is taken from the comparison chart supplied with the instrument. This contains Shore D, Rockwell B and C plus Brinell hardness.

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The Rockwell hardness test method consists of indenting the test material with a diamond cone, hardened steel or tungsten carbide ball indenter. The indenter is forced into the test material under a preliminary minor load F0 (Fig. 1A) of 10 kgf. When equilibrium has been reached, an additional major load F1, either 60, 100 or 150 kgf is applied with a resulting increase in penetration (Fig. 1B). When equilibrium has again been reach, the additional major load is allowed to dwell for a predefined time, before being removed, whist the preliminary minor load is still maintained. Removal of the additional major load allows a partial recovery, so reducing the depth of penetration (Fig. 1C). After a further dwell time the permanent increase in depth of penetration, resulting from the application and removal of the additional major load is used to calculate the Rockwell hardness number, using the following formula.

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The Rockwell Superficial hardness test method consists of indenting the test material with a diamond cone, hardened steel or tungsten carbide ball indenter. The indenter is forced into the test material under a preliminary minor load F0 (Fig. 1A) of 3 kgf. When equilibrium has been reached, an additional major load F1, either 15, 30 or 45 kgf is applied with a resulting increase in penetration (Fig. 1B). When equilibrium has again been reach, the additional major load is allowed to dwell for a predefined time, before being removed, whist the preliminary minor load is still maintained. Removal of the additional major load allows a partial recovery, so reducing the depth of penetration (Fig. 1C). After a further dwell time the permanent increase in depth of penetration, resulting from the application and removal of the additional major load is used to calculate the Rockwell hardness number, using the following formula.

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The Vickers hardness test method consists of indenting the test material with a diamond indenter, in the form of a pyramid with a square base and an angle of 136 degrees between opposite faces subjected to a test force of between 1gf and 100kgf. The full load is normally applied for 10 to 15 seconds. The two diagonals of the indentation left in the surface of the material after removal of the load are measured using a microscope and their average calculated. The area of the sloping surfaces of the indentation is calculated. The Vickers hardness is the quotient obtained by dividing the kgf load by the square mm area of indentation.

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