ASTM B392-03 pdf free.Standard Specification for Niobium and Niobium Alloy Bar, Rod, and Wire.
Samples for chemical and mechanical testing shall betaken from the finished material after all metallurgical process-ing to determine conformity to this specification. The samplesmay be taken prior to final inspection and minor surfaceconditioning by abrasion and pickling, and shall be represen-tative of the finished product.Care shall be exercised to ensure that the sampleselected for testing is representative of the material and that itis not contaminated by the sampling procedure.If there is anyquestion relating to the sampling technique or the analysisthereof，the methods of sampling and analysis shall be asagreed upon between the purchaser and the manufacturer.
A minimum of one sample from each lot of bars, rods,or wire shall be tested for tensile properties in the longitudinaldirection.
If endproduct chemical tests are required (6.3)，onechemical test shall be made from each lot of finished product.If any sample or specimen exhibits obvioussurface contamination or improper preparation, disqualifying itas a truly representative sample, it shall be discarded and a newsample or specimen substituted.In case of a failure, retest two additional specimens.If both retest specimens conform to this specification,discardthe original values and consider the material acceptable;otherwise, the lot shall be rejected or reworked and tested.12.4 If the results of the final tube inspections are not inconformance with the requirements of this specification, the lot may be reworked at the option of the manufacturer.The lotshall be acceptable if results of all tests，after reworking,conform to this specification.For the purposes of determining compliance with thespecified limits for requirements of the properties listed in thisspecification, an observed value or a calculated value shall berounded as indicated in accordance with the rounding methodof Practice E 29.Conduct tension tests in accordancewith Test Methods E 8. Determine the yield strength by the0.2 % offset method. Small size，1-in. (25.4-mm) gage lengthspecimens proportional to the standard specimen can be used.Determine tensile properties using a strain rate of 0.003 to0.007 in./in.min (.076 to .178 mm/mm·min) through the yieldpoint. After the yield strength has been exceeded, increase thecross-head speed to approximately 0.02 to 0.05 in./in. min(.500 to 1.27 mm/mm-min) to failure.If so specified on the purchase order， the purchaser orhis representative may witness the testing and inspection of thematerial at the place of manufacture. In such cases，thepurchaser shall state in his purchase order which tests hedesires to witness. The manufacturer shall give ample notice tothe purchaser as to the time and place of the designated test.Ifthe purchaser’s representative does not present himself at theagreed-upon time for the testing, and if no new date is set, themanufacturer shall consider the requirement for purchaser’sinspection at the place of manufacture to be waived. When theinspector representing the purchaser does appear at the ap-pointed place and time, the manufacturer shall afford him allreasonable facilities to see that the material is being furnishedin accordance with this specification.This inspection shall beconducted so as not to interfere unnecessarily with productionoperations.ASTM B392 pdf download.