Digester Outlet Device Scraper Arm Cracking

摘要

Continuous digester bottom scraper arms have been fabricated mainly out of carbon steel and 304L stainless steel. They are subject to unpredictable wear and cracking that makes it difficult to plan maintenance and can lead to frequent rebuilds and replacement. To alleviate this situation, scraper arms have recently been built out of 2205 duplex stainless steel. Experience has revealed however that for this application it is also susceptible to cracking. This paper covers cases that involve all of these materials. In addition to 2205 it also describes an option using Alloy 600 weld overlay that has offered good performance compared to the use of 304L liners.