Paper and Pulp
Pulp bleaching combines chlorine dioxide, low pH and elevated temperature, which is a specific and well-characterised attack on conventional stainless. 316L pits quickly in bleach plant service; 317L is the usual minimum, and duplex or 6-Moly grades are specified in the D-stage and washer environments.
What gets specified in paper & pulp
Ordered by how commonly they are called for in this sector.
- UNS S31700 / S31703317 / 317LPREN 30
Higher molybdenum than 316, at 3–4%. The step up before super-austenitics.
- UNS S31803 / S32205 / S32550 / S32750 / S32760Duplex / Super DuplexPREN 41
Roughly equal austenite and ferrite. Around twice the yield strength of 316L.
- UNS N08904904LPREN 35
High nickel, high molybdenum, with copper. Built for sulphuric acid service.
- UNS S31254254 SMOPREN 43
6% molybdenum super-austenitic with nitrogen. PREN above 42.
- UNS S31600 / S31603316 / 316LPREN 25
304 plus 2–3% molybdenum. The standard answer to chlorides and mild acids.
Applications
05- Bleach plant vessels and piping
- Digester and washer components
- Suction and press rolls
- Chemical recovery equipment
- Effluent handling systems
Governing standards
03- ASTM A240
- ASTM A312
- ASTM A790
Verification available
10- Spectrometer
- Chemical Testing Laboratory
- Positive Material Identification (PMI)
- Spectro Test
- Tensile Testing Machine
- Hardness Testing Machine
- Portable Hardness Tester
- Flattening Test
- Reverse-Bend Test
- Hydrostatic Test Machine
What paper & pulp buys
Other industries
Supplying into paper & pulp?
Send the specification and service conditions. We will confirm the grade, the availability and the documentation you will need.