Hi,
what are the likely microstructual effects that would be produced by heating a 5Cr/0.5Mo steel pipe to 700oC for several thousand hours? I am aware that the maximum operating temperature for this material is 650oC so would the extra temperature have a significnat effect? The heating...
Some furthur information on our technique for surface grinding. We remove a maximum of 0.1mm (0.004") at a time with the final pass being 0.05mm (0.002"). The wheel is 150mm diam and rotates at 6250 rpm and the sample is under coolant (water / cutting oil emulsion flush). The dry...
When preparing a welded sample for hardness surveys we have normally used a surface grinder to prepare both faces of the sample to ensure a flat parallel surface. The working surface is then further prepared (120 - 240 - 320 - 800 - 1200 wet grit) prior to etching for the hardness survey...
Here's a trick that an old fitter told me. Drill in from the cast iron side and tap the hole. Connect a high pressure hydraulic oil line and pump in oil as best you can. After 24 hours (longer is better some times) you would be suppried just how easy the hub will slip off.
Most suppliers would not carry C276 as a stock item so it would be a matter of asking the major suppliers if they would fabricate them for you. So I would try some like FASCO or similar supplier local to yourself.
As a long term user of Australian Standards I am curious to know if anyone outside Australia uses or applies these standards. U.S. standards (i.e. ASTM, SAE, ANSI, API) are extesnivly used here so I am interested in knowing if the reverse is the case anywhere.
The rapid screening test suggests an applied voltage of 20V. If the current density is achieved for the sample size does the voltage applied have any significant effect? or will any reasonable voltage less than 20V still achieve an acceptable result?
Any suggestions or thoughts would be...
Assuming the stainless steel type bearings are austenitic a simple magnet should seperate them. However the chrome steel bearings may need to be demagnetized after seperation.
Any surface breaking discontinuity can reduce the fatigue life of the material as it will tend to concentrate stresses locally and may therefore exceede the fatigue limit of the material. This will of course depend on the loading conditions and the sentitivity of the material to cracking.
Gary,
the theory behind cryogenic treatment is to finish off any martenisitic transformations that were not completed. Any retained austenite cuases localized stress due to its volumetric difference to martensite (approx 2%). By finishing off the transformation the internall stress are...
