A client asked Touchstone to conduct an investigation involving casting problems. By providing clear evidence of the defects and their probable causes, the client was able to work with his supplier to produce castings of the desired quality.
The following examples illustrate some of our contributions to this business sector:
- A manufacturer of pressure gages discussed the need to evaluate the corrosion protection offered by different manufacturing processes for cast aluminum parts. The objective of the accelerated corrosion testing was to compare the corrosion resistance of parts treated using the hernon hps 990 process, followed by three different post-impregnation treatments, with various other processes. The testing indicated that none of the three process offered any improvement in corrosion resistance for the parts being manufactured.
- Macrophotographs of rubber diaphragm materials produced by four different companies were provided for comparison to select the best supplier. Rapid turn-around for the client allowed selection in time to meet the contract production requirements of their client.
- Deflection tests were performed on ten spring specimens to determine the load required for total deflection. This information led to the selection of the best spring for an application.
- Salt Fog Corrosion tests according to ASTM B117 were performed on gage parts to verify compliance with customer requirements.
- Touchstone was asked to perform Shore Durometer “A” qualification tests on 13 rubber o-ring/lip seals, and various supply seats, found that variation between individual parts was within acceptable limits.
- Touchstone was asked to determine whether the proper sealant was used to impregnate small pores in aluminum regulator housings and body castings. Cuttings were removed from test pieces using a dry bandsaw, placed in the hot stage of a mass spectrometer, and heated from ambient to 300oC. The results indicate that either the wrong sealant may have been used, or the PC504 sealant was not properly cured.
- Several investment castings were examined using the unaided eye and a stereomicroscope. Both the inside and outside surfaces contained pores. The shape of the pores indicated that they were the result of gas that was entrapped during the casting process. The inside of the specimen also exhibited a defect known as “flow lines”. Previous experience with material of similar manufacture found this condition to be the result of low mold temperature. An elemental analysis was also performed.
- A client asked Touchstone to conduct an investigation involving casting problems. The two primary concerns centered on porosity from hydrogen gas, cold shuts due to casting problems, and shrinkage porosity due to metal feed and mold temperature. By providing clear evidence of the defects and their probable causes, the client was able to work with his supplier to produce castings of the desired quality.
- A piece which was thrown from a swedge in place on a gas well during an expolsion was examined by Touchstone scientists. The swedge was made from a 4 1/2″ diameter seamless pipe with one end swaged to 2″. TRL found that the swedge was made from AISE-SAE grade 1536 steel, and that the overall microstructure was tempered martensite which was consistent with the anticipated strength level of this material. The failure was not attributed to any material defect.
- Touchstone engineers have over 20 years of collective experience with pipe and coupling production including 15 years as chief metallurgist for a major supplier of pipe for the oil drilling industry. This experience includes expert testimony in legal action concerning accidents where the cause was demonstrated not to be related to pipe manufacture.
- A customer reported a failure in a heat transfer coil produced from 1 1/4″ standard black pipe. A sample of the pipe, with the failure included, was submitted for an investigation. It was concluded that the failure occurred because the fatigue strength of the steel, in a very localized area, was exceeded.
- A problem encountered by a drilling company involved the buildup of flammable gas in the ballast section of a crane. Discussions with the engineers found that the ballast section had been filled with miscellaneous scrap during construction of the crane and that the ballast tanks had been left open for a relatively long period prior to being welded shut. It was decided that the most probable explanation was that rust of the ballast had occurred with the attendant release of hydrogen gas. Without a vent, the gas pressure increased until the tank plates bowed. Safe pressure release was suggested through use of a tapping system used by the gas companies to tap natural gas lines without interruption of service.
The above examples are only a sample of our work in this area. We would be pleased to provide any additional information you may require. We also invite you to review examples on our website of work that we have performed in support of other business sectors.
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