ASTM E2598/E2598M-13
铸铁扬克和蒸汽加热干燥机的声发射检测标准实践

Standard Practice for Acoustic Emission Examination of Cast Iron Yankee and Steam Heated Paper Dryers

被代替

标准号

ASTM E2598/E2598M-13

发布

2013年

发布单位

美国材料与试验协会

替代标准

ASTM E2598/E2598M-21

当前最新

ASTM E2598/E2598M-21

 

 

引用标准

ANSI/ASNT CP-189 ASTM A278/A278M ASTM E1316 ASTM E2374 ASTM E543 ASTM E569 ASTM E650 ASTM E976

适用范围

5.1 Cast iron Yankee dryers can be up to 6.7 m [22 ft] in diameter, 7.3 m [24 ft] long, and weigh 91,000 Kg [100 tons], or more (refer to Fig. 1

FIG. 1 Yankee Dryer Drum

). Vessel thickness measurements are available from the paper/tissue machine operator. Cast iron is a brittle metal and has no specific yield point. Yankee dryers must maintain specific dimensional tolerances. When a pressurized Yankee or steam heated paper dryer (SHPD) remains stationary, it fills with condensate at a rapid rate. In an hour, a steam pressurized Yankee or SHPD can fill half way with condensate, doubling the weight on the frame, and the floor. Some Yankee owners have corporate requirements that a cast iron Yankee dryer remain stationary for ¹/₂ hour, then rotation is required. Permission is required, if the Yankee is to remain stationary for more time. This issue should be discussed with the responsible person prior to the examination.

5.2 Yankee dryers operate under a heated hood. The hood is in close proximity to the Yankee shell and allows only inches of clearance for the top half of the vessel.

5.3 Cast iron steam heated paper machine dryers are 2 m [6 ft] in diameter, or more, and may be 9 m [30 ft] long.

5.4 Grey cast iron experiences a continuing reduction in elastic modulus as it is stressed to increasing higher levels. It is prudent not to stress grey cast iron material beyond its operating stress level.

5.5 Flaws to be found are the same as those in any cast and machined product. Attempts have been made to characterize strength properties of cast irons in compact tension tests. In a TAPPI sponsored laboratory study, two out of three cast iron compact tension specimens experienced unplanned failures. From that experience it was cautioned that cracks initiated and grew faster than expected resulting in brittle fracture before the process could be halted. The failure of these two coupons demonstrated the rate in which cracks can grow in these materials and the material8217;s inability to stop a crack once it begins to grow. In each case, crack advance was extremely rapid and without warning. (See Note 1.)

Note 18212;Alleveto, C., and Williams D., Acoustic Emission Evaluation of Yankee Dryer Shell Material, 1991 TAPPI Engineering Conference Proceedings, pages 475-480.

5.6 Maximum Examination Pressure8212;Maximum Allowable Working Pressure for cast iron vessels is set based on ASME (Section VIII) pressure calculations based on thickness, radius, and material strength values, and will not exceed 10 bar [160 psi] and 230176;C [450176;F] (ASTM A278). When vessels are pressurized, anomalies produce emission at pressures less than normal fill pressure. Historically, if there is damage in a cast iron pressure boundary, AE activity will begin at load/stress levels less than 50 % of operating. Defects as small as 3 mm [¹/₈ in.] have been found using AE, during steam pressurization to operating pressure.

5.7 Pressur......

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