Recent content by isoca

Is it acceptable for ASME III code to complete a CMTR using OK or NOK instead of the numerical value? For example, in a production of 10,000 tubes, should the actual value of the external diameter of each tube be reported?

The test according to A262 should give OK under any condition. Note that for 316L the test must be performed in sensitized condition.

Stabilizing phases are formed at higher temperature than chromium carbide. If you reach the dissolution temperature of the stabilized carbides and then cool to a rate that does not allow their formation, when you heat up again the first thing that will form is chromium carbide (in the case that...

If you look at the Cu-Zn phase diagram you will observe that there are no phase changes for Zn contents less than 30/35%. Therefore there will be no quench hardening. For higher concentrations of Zn, hardening phases may appear but strictly it would not be hardening by quenching

Hay muchas maneras de verificar si son o no manchas de lubricante. Por lo pronto la mas simple es observarlas con mayor aumento. De cualquier manera si son aceptables o no dependerá de lo que indique la especificación del producto respecto a la calidad superficial requerida

Titanium nitrides are easily identifiable even in the as-polished condition (bright yellow cubic). In the case of titanium carbides, they are greyish-lavender with a more irregular shape. In any case, what is observed in the image does not appear to be any of them. You will probably find some of...

Titanium nitrides and carbonitrides are easily identifiable by their morphology and color when observed under an optical microscope. The nitrides are golden-yellow and the carbonitrides more lavender-like.

You can start by taking a look at the recommendations given by ASTM A380 and A967.

All those acids? mixed or pure? in what concentration? at what temperature? etc etc...

Ok thanks for the information. Obviously it is something that I asked the client, but sometimes the answers tend to come too late.

The tube is an ASTM A213. We have a lot of experience in manufacturing this type of tubes, however in this case the client requests that for the tensile test the elongation shall be taken using a gauge length equal to 5D where D is the equivalent diameter. What is not clear to me is the meaning...

Thanks for the answer, but I have a question. If the equivalent diameter is related to flow area (cross section?), where does it come from that it is equal to the ID? As far as I understand, the ASTM E8M indicates that the gauge length must be equal to 5D where D is the external diameter.

A client has sent us a specification to manufacture 316L tubes (12.7 mm OD) wich indicates the tensile test shall be carried out using a gauge length of 5D, where D is the equivalent diameter. My question is, what does it mean by "equivalent diameter"? The specimen shall be tested in full cross...

As mentioned before, stainless steel is always oxidized. Normally in this type of treatment, what is defined are several standards with different colors. What's your limit? totally bright? yellowish?. According to my experience, at atmospheric pressure the yellowing starts at around 400ºC (it`s...

Have you done a leak test on the furnace? Having vacuum does not mean that air is not entering it. Sometimes this issue is solved by covering the piece with a stainless steel sheet (free of visible oxide)