Debasis Q-1 : Hardness limit to meet MR 0175 means: weld, HAZ, parent metal. HAZ depends on the section thickness of the specimen being checked Close proximity means : HAZ and in the weld (usually). In any hardness measurement error factor due to placement. location of indentation and measurement error by viewer or instrument calibration or instrument usage - including that of digital measuring gauges used - should be within 2% of the limit specified. Error factor at the lower side of - 2% is fully agreeable / tolerable. Error factor of + 2% on specified limits of HRc should preferably avoided and should over-all meet MR 0175 limts. If individual readings exceed due to instrument or operator or placement or indentation errors, reading should be repeated to confirm this if it meets within the specified limit of HRc to MR 0175 limits. Q2: Individual inspector or III Party inspector should apply the above criteria while monitoring or viewing the results shown. For practising plant inspection team who use this more often in the field, the same applies also. Q 3. Answers to Q 1 and Q 2 should be followed Hope this helps you C.V.Srinivasan Nishi Engineers Pvt Ltd India Oct 10, 2007 E-mail: nishi@vsnl.com >It has been stated in MR-0175 that average of hardness in >close proximity ( though definition of close proximity is >not given ! ) should not exceed by the stipulated maximum >acceptable hardness as per relevant paragraph of the >section. It is also stated that NO INDIVIDUAL READING SHOULD >EXCEED BY 2HRc THAN THE MAXIMUM ACCEPTABLE HARDNESS AS >RECOMMENDED FOR DIFFERENT MATERIAL PER DIFFERENT SECTIONS. > >Q1. How much conservative the formula of 2HRc is ? >Q2. How the Inspectors/ 3rd Party Inspectors/ Users are >rationalising the formula for individual reading in >practical field ? >Q3. Any discussion/ arguments please share. > >best regards