FST&R’s Analytical Lab works closely with the physical and metallographic laboratories as a problem-solving tool in case of material failures. In addition, you can rely on FST&R’s Analytical Section for material-overcheck tests, referee tests, and product verification tests as an independent source.

Utilizing conclusive spectrometer technology in conjunction with ICP and Graphite Furnace AA, ensures quick turnaround by eliminating the need for lengthy wet chemical tests.

FST&R’s Analytical Lab also employs Optical Emission Spectrometry (OES or Arc Spark) for routine analysis of metals and their alloys. The OES has been designed specifically to meet the demands of quality assurance in the metal production and metal testing industries. OES technology is used for quick turnaround analysis of Iron, Aluminum, Copper, Cobalt, Titanium, and Nickel-based alloys.

Carbon, Sulfur, Hydrogen, Oxygen, and Nitrogen content in steel and titanium is determined by the inert gas fusion thermal conductivity method (utilizing C-S, N-O-H analyzer).

The analytical section has the capability to run various corrosion tests. The susceptibility to intergranular corrosion in wrought, nickel rich, chromium bearing, and stainless steels is detected using ASTM methods G28 , A262 and GB/T4334. Our environmental test unit is utilized for modified salt spray and copper-accelerated salt spray testing (ASTM G85 and ASTM B368). Pitting and crevice corrosion (ASTM G48) and Stress corrosion cracking in boiling magnesium chloride solution (ASTM G36) are among the other corrosion tests that can be performed.

The ASTM B117 Salt Spray Test is used to determine normal corrosion resistance to ocean water type environments, also GB/T 10125 and ISO 9227 can be performed. The ASTM B368 (CASS Test) is widely used to evaluate aggravated conditions such as road salt on automotive parts.

Typical materials analyzed include:

•Iron

•Aluminum

•Cobalt

•Titanium

•Inconel Alloys

•Low and high alloy Stainless Steels

•Bronze & Brass

ASTM B117 Salt Spray (Fog) Testing

ASTM B117 is the oldest and most widely used of the salt spray cabinet tests. Purportedly used as early as 1914 with roots in the National Bureau of Standards, and formalized as an ASTM B117 specification in 1939 by the American Society for Testing and Materials (ASTM). Early specifications for this method of Corrosion Testing were subject to much change.

The ASTM B117 Salt Spray (Fog) Test is often used to evaluate the relative corrosion resistance of coated and uncoated materials exposed to a salt spray or fog at an elevated temperature. Test specimens are placed in an enclosed salt spray cabinet or chamber and subjected to a continuous indirect spray of a neutral (PH 6.5-7.2) salt water solution. This climate is maintained throughout the duration of the test.

The water used in the ASTM B117 Salt Spray (Fog) Test must be compliant with the ASTM D1193 Specification for Reagent Water, Type IV; to this is added enough sodium chloride that a five percent salt solution is achieved. At the time the specimens are placed into the chamber, the cabinet should be pre-conditioned to the operating temperature of 35°C (95°F) and fogging a 5% salt solution at the required of 12ml/hr.

The default position for the sample placement is at a 15-30 degree angle from the vertical, although, automotive components are often tested in the "in car" position. Specimens should be placed in the cabinet so as to avoid any dripping of condensation from one specimen to another.

Except for the purposes of daily monitoringcollection rates, and for the rotation of test specimens, the cabinet shouldremain closed until the test is complete.

The ASTM B117 Salt Spray (Fog) Test can range in length from 24 to 5000 hours usually in increments of 24 hours.

Standard Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels

This specification covers the standard practices for detecting susceptibility to intergranular attack in austenitic stainless steels. These practices include five intergranular corrosion tests, namely: (1) oxalic acid etch test for classification of etch structures of austenitic stainless steels; (2) ferric sulfate-sulfuric acid test, (3) nitric acid test and (4) copper-copper sulfate-sulfuric acid test for detecting susceptibility to intergranular attack in austenitic stainless steels; and (5) copper-copper sulfate-50% sulfuric acid test for detecting susceptibility to intergranular attack in molybdenum-bearing cast austenitic stainless steels. Methods for preparing the test specimens, rapid screening tests, apparatus setup and testing procedures, and calculations and report contents are described for each testing practice. The etch structure types used to classify the specimens are: step structure, dual structure, ditch structure, isolated ferrite, interdendritic ditches, end-grain pitting I, and end-grain pitting II.

The ASTM B 368 Copper-Accelerated Acetic Acid Salt Spray, (CASS) Test

This test is performed in accordance with the specifications found in the ASTM B 368 - Standard method for Copper Accelerated Acetic Acid Salt Spray (Fog) Testing (Cass). A standard ASTM B117 salt fog cabinet is employed. A 5% sodium chloride solution is used, with the addition of 1 gram of copper chloride dihydrate per each 3.8 liters of salt solution. The solution is then adjusted to a ph of 3.1-3.3 by adding acetic acid, and the temperature is adjusted to the same range as for the neutral salt spray (ASTM B117), and the acetic acid salt spray (ASTM G 85).

The CASS Test is widely used for research and development, simulated service evaluation, manufacturing control, and specification acceptance. It was developed specifically to test nickel/chromium and copper/nickel/chromium electrodeposited coatings. And it is also used to determine the corrosion resistance of various aluminum alloys.

ASTM G85 Annex A1 Standard Practice for Modified Salt Spray (Fog) Testing

ASTM G85 Annex A1 Acetic Acid-Salt Spray Test, Continuous In this variation of the basic Salt Spray Test the 5% sodium chloride solution is acidified to a ph of 3.1 to 3.3 by adding acetic acid. The temperature in the Fog chamber is maintained at 35°C + 1.1 or-1.7°C (95°F+2 or -3°F).

This test may be as short as 16 hours. But it is often run for 144 hours or even as long as 240 hours. At these extended lengths it is very useful for researching parameters associated with the electroplating of decorative chrome plating of die-cast steel or zinc. It is also used for the evaluate on of quality in a product.

ASTM G85 Annex A2 Standard Practice for Modified Salt Spray (Fog) Testing

ASTM G85 Annex A2 Cyclic Acidified salt Fog Testing. For this variety of the Salt Spray Fog Test the standard 5% sodium chloride solution is acidified to a ph of 2.8 to 3.0 by adding the proper amount of acetic acid. The temperature in the exposure zone is maintained at 49°C +1.1 or -1.7°C (120°F +2 or -3°F).

This test is usually run under what is referred to as 'wet bottom' conditions. This prevents the inside of the box from drying out. Dry conditions would decrease the corrosion rate.

However, for testing 2000 series aluminum alloys and some paint coatings a dry bottom test is preferred.

The test is run as a series of six hour cycles. These cycles consist of: 3-4 hr. spray, 2 hr. dry-air purge, followed by 3 and 1/4 hr. soak at relative high humidity.

ASTM G85 Annex A3 Standard Practice for Modified Salt Spray (Fog) Testing

This test uses a solution of sea salt in place of the standard sodium chloride. This solution is then acidified with the use of Acetic acid until a ph of 2.8 to 3.0 is maintained.

This test is performed as a wet bottom test, i.e. about an inch or so of water should always be present at the bottom of the chamber to prevent the inside of the box from becoming dry, which would decrease the corrosion rate.

The temperature remains constant during this test. The temperature that the test is to run under is determined by the type of material being tested.

This test is particularly useful in production control of exfoliation resistant heat treatments for the 2000, 5000, and 7000 series aluminum alloys.

ASTM G85 Annex A4 Salt/So2 Spray (Fog) Testing

This test involves a salt spray fog with the addition of Sulfur Dioxide (SO2) gas directly into the salt spray testing chamber or cabinet. The salt spray solution is defined either by mutual agreement or by the specifications covering the material or product to be tested.

The temperature in the exposure zone of the salt spray cabinet or chamber is kept at a constant 35°C + 1.1 or - 1.7°C (95°F + 2 or - 3°F).

The (SO2) gas should be introduced into the salt spray cabinet in a manner that insures a uniform dispersion within the chamber.

The cycle of So2 introduction depends on the specifications of the material or product being tested, or is determined by mutual agreement. A couple examples of commonly used cycles for this test are:

•Constant spray with introduction of SO2 gas for 1hr 4 times a day (every 6 hrs)

•1-2-hr salt spray, 1-2-hr SO2, and 2-hr soak

ASTM G85 Annex A5 Dilute Electrolyte Cyclic Fog/Dry Test

In this test cycles of 1hr dry-off and 1hr fog are utilized. The electrolyte is a solution of sodium chloride and ammonium sulfate and is more dilute than the traditional salt spray fog test. The fog portion of this test is conducted at room temperature, the dry-off portion, however, is performed at an elevated temperature. Also the spray atomizing air is not saturated with water for this test.

The electrolyte solution consists of 0.05% sodium chloride and 0.35% ammonium sulfate by mass. The sodium chloride and water are subject to the same purity requirements as for the other test in this specification. The ammonium sulfate shall not contain more than 0.3% total impurities. The temperature throughout the exposure zone during the dry-off phase shall reach and remain constant at 35°C plus or minus 1.5°C (95°F plus or minus 3°F) within 3/4-h of switching from the fog period to the dry period.