ASTM E140 specifies different minimum indentation loads for Vickers hardness in order for the measurement to be considered valid to use for conversion to other hardness scales. These minimums are:
Non-Austenitic SteelNo limit
Nickel Alloys1 kg
Cartridge Brass (70-30)No Limit
Copper100 g
White...
Is the point count method specified by ASTM E562 an accurate means to determine percent delta ferrite in martensitic steels? What alternate method can be used? Any experience is helpful.
I came across a claim during literature review for a failure that "HE failures are ALWAYS intergranular". I want to know what you think.
Specifics to the situation I am working with: I have fractured CrMoV high-strength martensitic steel fasteners that exhibit quasi-cleavage fracture. Can this...
A few years ago I asked how everyone reported their hardness results. It seemed like every respondent reported in a different way.
With digital Rockwell testers now the norm, I want to ask: do you report to the 0.1 point or do you round to the nearest integer value. Do you think the wording of...
Would you expect carburization to increase residual surface stress in a low carbon steel? Component is a machined tubular component with 60 mil wall and 13 mil effective case depth on OD & ID. Material is a low carbon (0.05%) steel that has been resulfurized and rephosphorized.
Can I expect this steel to have good Charpy impact resistance down at sub-zero temperatures (say, -40 deg. F)? If so, why? I have been told A1011 was developed for Arctic applications, but I have not found any published references in my search . I do notice that impact testing is not among...
I need to confirm the presence of Type II coating (formed by treating aluminum alloys electrolytically in a bath containing sulfuric acid to produce a uniform anodic coating on the surface). My method was to test the surface using EDS at 10 keV to detect sulfur, the theory being that the...
I wanted your thoughts: I have a galvanic coupling between a leaded brass component and aluminum foil that wrapped around a polymer jacket. The coupling may see moisture on occasion and prevention of galvanic corrosion of the aluminum has been specified. For practical reasons, the aluminum...
Galvanic corrosion can be mitigated by having an anode with a large area relative to the cathode. My question: Are the relative areas only the areas in contact with the electrolyte, or are they the total areas? This does not seem to be addressed in the references I have. Thanks!
I recently evaluated a couple of cracked brass components (from different components and customers) where cracking was transgranular and single cracks, with no branching. Stress corrosion cracking was determined to be the failure mechanism after we realized both components had been exposed to...
Assume a chrome-plated alloy-steel component that can be susceptible to hydrogen embrittlement (>40 HRC). Questions:
1.Would hydrogen always be present in identifiable quantities if hydrogen embrittlement occurred either because of insufficient bake-out or baking starting too late?
2. If so...
I have a 2 part question where I am interested in how people report Rockwell hardness results for testing performed under ASTM E18:
1. When you use a modern digital tester that records hardness to 0.1 point precision, to what degree of precision do you report your results (i.e. 0.1 point or...
Stress corrosion cracking of carbon and low alloy steels has been documented in certain mixed concentrations of CO-CO2-H2O. All of the literature I have reviewed has explained that all 3 of these components must be present. Does anyone know if there is any documentation where the mix is just...
I recently dealt with a modern version of an SAE cast iron spec (SAE J431) which used the preferable units for hardness as MPa. I had never seen this before. I understand the logic of how one could use these units, but I have never seen hardness testers report in MPa either. SAE in the spec...
How do I calculate the amount of applied torque required for a fuel fitting tee from a truck diesel engine? The tee is made from 316 SS, with couplings made from carbon steel on the two branches at the top of the tee, while the outlet has a flanged 316 coupling that screws into a valve, with...
Does it make sense for cast CF8M (i.e. 316 chemistry) to sensitize in the HAZ adjacent to the weld if the casting is post-cast weld repaired and is used in water service? Selective attack is occurring in the ferrite in the austenite matrix below selective corrosion adjacent to the weld. Carbon...
In a recent thread we discussed differences in measured Vickers microhardness when using different loads despite the basis of the procedure as-published that there should be no difference. The April 2012 issue of Advanced Materials & Processes has a good paper by George Vander Voort and Ryan...
I am trying to identify the source for a tin bronze bearing alloy containing 1.5% Pb and 2.2% Bi. It is a dry bearing and these elements add lubricity. I can understand the presence of either lead or bismuth but not the presence of both together. I checked the UNS copper alloys (i.e. CDA) but...
