Standard Practice for Assessing the Tendency of Industrial Boiler Waters to Cause Embrittlement (USBM Embrittlement Detector Method)
|Publication Date:||1 November 2005|
|ICS Code (Boilers and heat exchangers):||27.060.30|
This practice,(Footnote 3) known as the embrittlement-detect
NOTE 1 - The embrittlement detector was designed to reproduce closely the conditions existing in an actual boiler seam. It is considered probable that the individual conditions of leakage, concentration, and stress in the boiler seam can equal those in the detector. The essential difference between the detector and the boiler is that the former is so constructed and operated that these three major factors act simultaneously, continuously, and under the most favorable circumstances to produce cracking; whereas, in the boiler the three factors are brought together only under unique circumstances. Furthermore, in the detector any cracking is produced in a small test surface that can be inspected thoroughly, while the susceptible areas in a boiler are large and can be inspected only with difficulty. In these respects the embrittlement detector provides an accelerated test of the fourth condition necessary for embrittlement, the embrittling nature of the boiler water.
NOTE 2 - Cracks in a specimen after being subjected to this test indicate that the boiler water can cause embrittlement cracking, but not that the boiler in question necessarily has cracked or will crack.
The effectiveness of treatment to prevent cracking, as well as an indication of whether an unsafe condition exists, are shown by this practice. Such treatments are evaluated in terms of method specimen resistance to failure.
The practice may be applied to embrittlement resistance testing of steels other than boiler plate, provided that a duplicate, unexposed specimen does not crack when bent 90° on a 2-in. (51-mm) radius.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Footnote 3 - This test method was developed during an investigation conducted under a cooperative agreement between the Joint Research Committee on Boiler Feedwater Studies and the United States Bureau of Mines.
For information on the development of this test method reference may be made to the following:
Schroeder, W. C. and Berk, A. A. "Intercrystalline Cracking of Boiler Steel and Its Prevention," Bulletin 443, U.S. Bureau of Mines, 1941.
Schroeder, W. C., Berk, A. A. and Stoddard, C. K. "Embrittlement Detector Testing on Boilers," Power Plant Engineering, Vol 45, August, 1941, pp. 69-76.
"Embrittlement Symposium," Transactions of the Am. Soc. Mech. Engrs., Vol 64, 1942, pp. 393-444.
Whirl, S. F. and Purcell, T. E. "Protection Against Caustic Embrittlement by Coordinated Phosphate-pH Control," Proceedings, Third Annual Water Conference, Engrs. Soc. of Western Penna., 1942, pp. 45-60.
Berk, A. A. and Schroeder, W. C. "A Practical Way to Prevent Embrittlement Cracking," Transactions, Am. Soc. Mech. Engr., Vol 65, 1943, pp. 701-711.