Numerous accelerated corrosion tests may be performed in the Shanghai Linpin salt spray climate chambers, including AS 2331.
This Standard sets out the method for the Acetic acid salt spray test (ASS test) and Copper accelerate acetic acid salt spray test (CASS test) for the assessment of corrosion resistance of inorganic and organic coatings on metallic substrates.
It is important that the results obtained from the test are not regarded as having a direct correlation with environments in which items may be exposed in service or as indicating the relative corrosion resistance of different coatings.
The test procedures described in this Standard do not necessarily include all of the precautions required to satisfy health and safety aspects. Care should be taken to ensure that the procedures are carried out only by people who have received suitable training. Guidance in the handling and use of hazardous chemicals is given in AS/NZS 2243.1 and AS/NZS 2243.2.
The following apparatus is required:
(A) Spray cabinet:
The spray cabinet shall be made of or lined with, materials resistant to corrosion by the test solution. The cabinet shall have a volume of not less than 0.2 m3 and.preferably not less than 0.4 m3 since, with smaller volumes, difficulties are experienced in ensuring an even distribution of spray.
The size and shape of the cabinet shall be such that the quantity of solution collected in the cabinet is within the limits stated in Clause 7.1. The upper parts of the cabinet shall be designed to ensure that drops of accumulated test solution do not drip onto test pieces.
Adjustable baffles may be used to prevent direct impingement of spray on test pieces and to assist the uniform distribution of spray throughout the cabinet.
(B) Test piece supports:
Test piece supports shall be made of inert non-metallic material such as ceramic, glass, plastic, or suitably coated wood.The material used for suspending test pieces shall be synthetic fibre, cotton thread or other inert insulating material.
(C) Atomizing equipment:
The cabinet shall be equipped with means to spray the test solution and shall include
(i) a supply of clean compressed air of controlled pressure and humidity;
(ii) a reservoir to contain the stock of test solution;
(iii)one or more atomizers made of chemically inert material.
The compressed air supply to the atomizers shall pass through a filter to remove all traces of oil and solid matter and shall be at a pressure of 70 KPa to 170 KPa.
To prevent evaporation of water from sprayed droplets of test solution, the air shall be humidified before entering the atomizer by means of a saturation tower. The saturation tower shall contain water at a temperature several degrees higher than that of the cabinet. The actual temperature to be used is dependent on the air pressure and on the type of atomizer nozzle, and shall be adjusted to enable the rate of collection and the concentration of collected spray to be maintained within the limits specified in Clause 7.1.
(D) Collecting containers:
At least two containers to collect sprayed test solution are required. Such containers shall comprise graduated cylinders, or similar, made of glass or other chemically inert material and shall incorporate the stem of a similarly inert funnel inserted through their stoppers.
(E) Temperature control:
The cabinet shall be fitted with equipment and instruments capable of supplying and controlling heat to maintain the cabinet and its contents at the specified test temperature (see Clause 7.1). The controller shall be a thermostat element placed either within the spray cabinet at least 100 mm from the walls or in a water jacket on the cabinet. In either case a thermometer shall be placed within the cabinet at least 100 mm from the walls and shall be capable of being read from outside the cabinet.
Purity:
All chemicals used shall be of a recognized analytical reagent grade. The water used shall be distilled or deionized having a conductivity of not greater than 20 uS/cm or, alternatively, shall not contain greater than 200 mg/L of dissolved solids.
Preparation of test solution:
The acetic acid salt spray test solution shall be prepared as follows:
The neutral salt spray test solution shall be prepared by dissolving sodium chloride in distilled or deionized water to produce a concentration of 50 ±5 g/L.
The pH of the salt solution shall be adjusted to enable the pH of sprayed solution collected within the test cabinet to be in the range 3.1 to 3.3.
The CASS test solution shall be prepared as follows:
The first two steps are the same as above, and the following step is added.
Dissolve a sufficient amount of copper chloride dihydrate (CuC12.2H20) in the salt solution to produce a concentration of 0.26 ±0.02g/L.
Procedure: Cabinet operating conditions
The test cabinet shall be operated in accordance with the following conditions using the test solution specified in Clause 5
(a) Test cabinet temperature: 35 ±2℃
(b) pH of collected test solution: 3.1 to 3.3
(c) Average collection rate of sprayed test solution over a minimum period of 24 h for a horizontal collecting area of 80 cm: 1 mL/h to 2 mL/h
(d) Concentration of NaCl in collected test solution: 50±10 g/L
Exposure of test piece:
Test pieces should, in principle, be flat and placed so that the test surface is facing upwards at an angle as close as possible to 20°to the vertical. This angle shall. in all cases, be within the limits of 15°to 30°. For irregular surfaces, e.g. entire components, these limits shall be adhered to as closely as possible.
Duration of tests:
Recommended periods of exposure are 2 h, 6 h, 24 h, 48 h, 72 h, 96 h, 168 h, 240 h, 336 h, 480 h, 720 h or 1000 h.
Typical Spray cabinet for ASS and ACSS test:
If you are still interested in any kind of environmental test chambers, and I'm pleased provide some of our details and project to you. That's more, at present we have more attractive price for you. Welcome for inquiry any time, I will reply asap!
If you want to know more information about climate chambers or our company, please feel free to contact sales@lenpure.com or visit http://www.lenpure.com/ .
