Application specification brief
Stainless Steel for Pulp & Paper Processing
Select by mill stream. Cooking, washing, bleaching, recovery, evaporation, stock preparation, white water, wet end, utilities, and effluent create distinct liquor, chloride, sulfur, pH, solids, deposit, and shutdown conditions. Define each stream and material zone before comparing grades. The owner, licensor, corrosion specialist, and designer retain final approval.
Send the service, product form and inspection plan. We quote the matching stainless product forms; the project authority keeps final service approval.
Four-state review
Service Boundary
Review the complete operating cycle, not only nominal process conditions.
Normal operation
Name the stage, liquor or stock, species and ranges, pH, chloride, redox condition, sulfur compounds, solids, fiber or grit, temperature, pressure, velocity, aeration, residence, and deposits.
Cleaning and maintenance
Provide wash, boil-out, acid or alkaline cleaning, bleach carryover, biocide, water quality, concentration, temperature, duration, rinse, neutralization, drainage, and return procedure.
Shutdown and standby
State whether equipment is drained, washed, steamed, dried, left full, or exposed to air; identify retained liquor, pulp mats, crevices, wet insulation, condensate, deposits, and duration.
Upset and abnormal cases
State chemical overcharge, pH or oxidant excursion, chloride contamination, evaporation concentration, temperature or flow loss, liquor carryover, stream mixing, stagnant hold, and incomplete startup cleaning.
Inputs before the RFQ
Operating Environment
| Variable | What to review | Procurement impact |
|---|---|---|
| Process stage and stream identity | Use equipment tags and flow diagrams to separate cooking, washing, bleaching, recovery, stock, white-water, utility, and effluent duties. | Prevents one alloy schedule being applied across unrelated chemistries and assigns product, fabrication, inspection, and owner approval by zone. |
| Chemical envelope | Provide all important species, pH, chloride, sulfur compounds, oxidants, reducing agents, dissolved solids, contaminants, and normal-to-upset ranges. | Supports corrosion screening, test selection, weld and surface requirements, and explicit exclusions from the material requisition. |
| Solids, deposits, and flow | State pulp consistency, fibers, scale, sand, liquor solids, velocity, turbulence, impingement, settling, washing efficiency, and cleanability. | Connects under-deposit and erosion risks to grade, thickness, geometry, pump and piping components, surface, and inspection access. |
| Shutdown and carryover | Map residual liquor, bleach carryover, deposits, wash water, oxygen entry, condensation, dead legs, insulation wetting, outage duration, and restart sequence. | Makes off-line exposure part of material selection, cleaning, preservation, corrosion allowance, access, and outage inspection planning. |
Design and fabrication risks
Failure Modes and Controls
| Failure mode | Drivers to review | Specification control |
|---|---|---|
| Pitting and crevice corrosion | Chloride, oxidizing chemicals, deposits, gaskets, shielded zones, stagnant wash water, rough welds, heat tint, and concentration during evaporation or drying. | Use stream and shutdown data, reduce crevices, control deposits, select a project margin, restore fabricated surfaces, and obtain owner materials review. |
| General or selective chemical attack | Strong acidic or alkaline liquor, sulfur species, oxidant or reducing potential, temperature, concentration, contaminants, phase separation, and mixed streams. | Define the actual chemical envelope and materials condition, use project corrosion evidence where required, and segregate duties that need different alloys. |
| Erosion-corrosion and under-deposit damage | High-solids liquor or stock, abrasive particles, impingement, flashing, two-phase flow, poor distribution, settled fibers, scale, and inaccessible cleaning. | Provide hydraulic and solids data, improve geometry and cleaning, review thickness and material by location, and define inspection of wear-prone zones. |
Screening ladder
Material Selection
Grades are screening routes, not unconditional substitutes. Product standards, fabricated condition, and project approval still govern.
| Grade reference | Where to screen it | Approval boundary |
|---|---|---|
| 316L Stainless Steel | Quote for general mill piping, tanks, machine components, and moderate process zones supported by stream-specific review. | Bleach stages, hot chlorides, deposits, reducing liquors, evaporation, welds, shutdown, and upset chemistry can require another route. |
| 2205 Stainless Steel | Quote for chloride-bearing liquor, vessel, piping, and structural duties where duplex strength and corrosion margin fit the design. | Phase balance, toughness, product form, forming, welding, heat treatment, deposits, service chemistry, and owner qualification still govern. |
| 2507 Stainless Steel | Quote for severe chloride or oxidizing zones identified by the mill corrosion study and equipment design. | Do not infer universal bleach or liquor suitability; temperature, crevices, process variability, product form, fabrication, and testing remain specific. |
| 254 SMO Stainless Steel | Quote for aggressive bleach, high-chloride, or deposit-prone duties when the corrosion basis supports a 6Mo austenitic route. | Confirm contracted grade, form, temperature, stress, weld consumable and procedure, cleanliness, testing, and owner materials acceptance. |
Supply route
Product Forms and Ordering Basis
| Form | Typical scope | Order basis |
|---|---|---|
| Plate and sheet | Digesters, towers, washers, vats, tanks, chests, evaporator parts, hoods, ducts, floors, screens, and machine components. | State grade, material standard, condition, thickness, dimensions, tolerances, forming, surface, tests, corrosion allowance, and traceability. |
| Pipe and tube | Liquor, bleach, stock, white-water, chemical, steam, condensate, wash, effluent, exchanger, and instrument lines. | Define material and dimensional standards, seamless or welded route, NPS or OD, wall, length, ends, heat treatment, surface, tests, cleanliness, and marking. |
Delivered condition
Fabrication, Welding, Surface, and Cleaning
Material zoning and traceability
Issue equipment and piping material maps by process stream, retain heat and item identity through cutting and assembly, and control substitutions through owner review.
Forming and welding
Qualify base and filler combinations, forming strain, joint design, purge, heat input, interpass, duplex controls, repair cycles, NDT, and any required heat treatment for actual thickness and position.
Surface restoration and cleanliness
Remove embedded iron, scale, slag, spatter, and detrimental heat tint; define grinding limits, pickling or passivation if invoked, rinse-water quality, cleanliness, drainage, and inspection.
Release evidence
Inspection and Documents
| Stage | Required evidence |
|---|---|
| Materials and design approval | Submit process data, corrosion basis, material requisitions, standards and editions, zone maps, drawings, procedures, deviations, and inspection plan to the named authority. |
| Raw material | Verify certificates, heat identity, chemistry, mechanical and heat-treatment results, dimensions, condition, surface, PMI scope, and ordered corrosion or phase tests. |
| Fabrication | Record material and weld maps, forming, consumables, procedures and operators, parameters, repairs, NDT, dimensions, surface treatment, cleanliness, and traceability. |
Continue the specification
Related Standards and Grade Decisions
Product and dimensional standards
Related grade comparisons
Buyer questions
Frequently Asked Questions
Is 316L suitable throughout a pulp mill?
No. It serves many general areas, but bleach chemicals, hot chlorides, reducing liquors and deposit-prone zones can require different alloys.
Why use duplex stainless in mill equipment?
Duplex grades add strength and chloride resistance, which can suit vessels and piping when welding and phase balance are controlled.
What process data belongs in the RFQ?
Name the process stage, chemicals and concentrations, temperature, solids, velocity, cleaning cycle, shutdown condition and design code.
Published by Tsingshan (Shandong) Iron & Steel Co., Ltd..Sources, update policy and technical limitations.
Quotation package
What to Include in the RFQ
- Mill area, equipment tag or piping class, flow diagram, owner and licensor specifications, code, and approval authority
- Stream species and ranges, pH, chloride, sulfur and redox chemistry, contaminants, phases, pulp consistency, solids, deposits, and sampling basis
- Normal, design, cleaning, shutdown, startup and upset conditions, flow, velocity, heat transfer, aeration, cycles, abrasion, and corrosion allowance
- Grade and form by material zone, product and dimensional standards with editions, route, condition, dimensions, tolerances, quantity, surface, and interfaces
- Forming, machining, welding, filler, purge, heat input, duplex controls, treatment, contamination prevention, cleaning, test water, and preservation
- PMI, mechanical, corrosion or phase tests if specified, NDT, pressure test, dimensions, surface, cleanliness, witness points, certificates, traceability, material maps, and deviations
Quote request
Get a Stainless Steel Quote
Send the product, grade and quantity you already have. We will complete the specification and quote the supply route.