904L Cold Rolled Stainless Steel Sheet AISI ASTM 2B Surface Stainless Steel Sheet For Industry

Grade Standard: AISI & ASTM compliant UNS N08904 super austenitic low-carbon high-alloy stainless steel

Production Technology: Precision multi-pass cold rolling, full homogenization bright annealing, online flatness rectification, uniform 2B finished surface treatment

Surface Feature: Standard industrial 2B matte fine finish, compact dense surface without pitting and oxide inclusion, customized BA / No.4 available upon demand

Core Alloy Configuration: Ultra-low carbon + high Cr-Ni + excess copper & molybdenum composite alloy design, super resistance to mixed inorganic acid, dilute sulfuric acid, phosphoric acid and high-concentration chloride medium

Differentiated Core Advantage: Distinct from conventional 316/317 stabilized or low-carbon stainless series relying only on molybdenum for anti-corrosion, 904L belongs to super austenitic premium anti-corrosion grade with composite alloy system, targets ultra-harsh mixed acid industrial environment where all ordinary 300-series stainless steel fails rapidly; pure industrial positioning for severe corrosive production lines

Application Orientation: Sulfuric acid & phosphoric acid chemical production equipment, non-ferrous metal pickling tank lining, fertilizer manufacturing plant facilities, coastal ultra-high salt chemical workshop and waste liquid recycling anti-corrosion structure

904L cold rolled stainless steel is a high-end super austenitic anti-corrosion material beyond conventional 300-series standard stainless steel, completely separated from titanium-stabilized 321, niobium-stabilized 347 heat-resistant steel and molybdenum-bearing 316/317 anti-chloride steel. While 316L/317L can only cope with weak acid and conventional salt fog working conditions and fail quickly once exposed to dilute sulfuric acid and mixed acid medium, 904L adopts exclusive high nickel plus copper-molybdenum synergistic alloy formula. Copper element greatly improves the material’s inherent tolerance to sulfuric acid erosion, and high molybdenum further strengthens resistance against chloride pitting and crevice corrosion, realizing stable long-term service under continuous mixed acid immersion environment. All our products are manufactured strictly following AISI and ASTM specifications, unified standard 2B cold rolled finish as mainstream delivery state; after closed annealing and fine rolling, the plate features consistent thickness tolerance, superior flatness and seamless compact surface structure, effectively avoiding corrosive medium infiltration caused by surface defects. Every batch completes full chemical composition and mechanical property testing before delivery to satisfy international industrial project inspection and import customs clearance requirements.

The core competitiveness of ASTM standard 904L stainless steel lies in its multi-element synergistic anti-corrosion mechanism, which is the essential difference from single-alloy modified ordinary stainless steel. Conventional molybdenum stainless steel only depends on molybdenum to resist chloride corrosion without effective sulfuric acid resistance; high-nickel single-alloy steel cannot bear high chloride concentration working condition. However, the matched addition of Cu, Mo, Cr and Ni inside 904L forms dense passivation film rapidly when contacting dilute sulfuric acid, phosphoric acid and mixed acid solution, blocking continuous medium corrosion toward metal matrix. Even under long-term full immersion in low-concentration sulfuric acid environment, the material will not produce uniform corrosion and perforation damage, which cannot be achieved by any 300-series conventional stainless grades. Meanwhile, ultra-low carbon design eliminates sensitization risk during welding and high-temperature construction, no intergranular corrosion occurs at welding joints after field large-area splicing assembly without extra post-weld heat treatment.

In mechanical performance, super austenitic microstructure endows 904L stable toughness and non-magnetic characteristic after cold working, no magnetic transformation after bending and stamping forming. Different from high-alloy duplex steel with poor cold forming performance, precision cold rolling and full stress-relief annealing optimize internal grain uniformity of 904L cold rolled sheet, enabling smooth cold bending, deep drawing and all kinds of conventional welding processing without cracking and edge brittle failure. Our standardized 2B surface is formed by continuous pickling and fine leveling after cold rolling, the dense and uniform surface structure reduces the adhesion of corrosive residue and medium sediment, further improving the long-term anti-corrosion stability of finished industrial equipment.

In terms of temperature adaptability, 904L maintains stable anti-corrosion performance within -20℃~90℃ conventional industrial working temperature range; it is not developed for ultra-high temperature working condition like 321/347 heat-resistant steel, thus the alloy proportion abandons redundant high-temperature strengthening element, balancing outstanding anti-corrosion ability and reasonable raw material cost for acidic industrial projects.

It is the exclusive designated lining material for dilute sulfuric acid storage tank, phosphoric acid reaction tank, fertilizer production acid mixing equipment and chemical pickling trough. The composite alloy structure steadily resists long-term erosion of mixed inorganic acid raw materials, solving the frequent replacement problem of 316/317 equipment corroded and perforated within short service cycle. Most chemical enterprises adopt integral 904L plate welding to make tank body inner lining for long-cycle continuous production.

Widely used for metal pickling pool inner panel, electroplating waste liquid collecting tank, smelting waste acid recovery pipeline and auxiliary anti-corrosion structural plate. The pickling environment features high chloride plus residual sulfuric acid mixed medium, ordinary stainless steel will appear serious spot corrosion within several months, while 904L can keep intact structure for many years under continuous alternating immersion and splash erosion.

Applied for coastal chemical factory waste water treatment equipment, high-salt waste liquid sedimentation tank and outdoor chemical raw material storage outer protection shell. It bears dual damage of coastal salt fog atmospheric corrosion and industrial waste acid volatile medium erosion, becoming irreplaceable anti-corrosion raw material for coastal severe corrosive industrial construction.

Used for desulfurization waste liquid processing cabinet, acidic waste gas washing tower inner lining and industrial hazardous waste leachate storage equipment. The complex mixed corrosive medium inside environmental protection equipment can rapidly damage all molybdenum stainless steel below 317 grade, while 904L meets long-term stable operation requirement of high-standard environmental protection projects.

904L cold rolled sheet with original 2B surface is covered with anti-scratch PVC protective film during factory packaging to prevent surface scratch during cutting, transportation and field installation; the protective film is removed only after full construction completion to keep original compact 2B finish intact. During welding construction, argon arc welding is the preferred processing method to reduce welding heat affected zone; reasonable welding parameter control can avoid excessive high temperature damaging local passivation performance of base material.

Daily maintenance cost of finished industrial facilities made from 904L is far lower than other anti-corrosion metal materials. Regular clean-up of tank surface residual acid sediment and medium residue with clean water can effectively prolong service life; avoid long-time local accumulation of high-concentration strong acid at dead corners of equipment. Thanks to stable composite passivation film, no regular anti-corrosion coating and anticorrosive paint brushing are required all year round, greatly reducing enterprise later-period equipment maintenance and shutdown loss caused by corrosion damage.

First, unique Cu-Mo-Cr-Ni multi-alloy synergistic formula brings industry-leading resistance to dilute sulfuric acid and mixed acid, core advantage unavailable for all conventional 300-series stainless steel, the best solution for severe acidic industrial anti-corrosion projects.

Second, strict AISI and ASTM full-process production and inspection system provides complete mill test certificate and component inspection report, smoothly passing global industrial engineering acceptance and import customs clearance procedures.

Third, standardized fine 2B cold rolled finish balances processing practicability and anti-corrosion performance, avoiding extra surface polishing cost for hidden lining structural parts.

Fourth, ultra-low carbon design realizes zero post-weld sensitization corrosion, simplifying on-site large-area welding construction procedure of industrial tank equipment.

Fifth, moderate cold forming performance adapts to diversified cutting, bending and welding processing demands of non-standard industrial equipment, lowering finished product rejection rate.

Sixth, factory direct bulk production controls comprehensive cost, providing stable supply and competitive bulk price for long-term cooperation of large chemical and environmental protection enterprises.

We can provide free sample testing service, customized size cutting solution and latest factory bulk quotation according to your actual corrosive medium and working condition parameters.