{"id":14134,"date":"2026-08-05T16:48:39","date_gmt":"2026-08-05T08:48:39","guid":{"rendered":"https:\/\/jiuguangmetal.com\/?post_type=news&p=14134"},"modified":"2026-08-05T16:58:43","modified_gmt":"2026-08-05T08:58:43","slug":"stainless-steel-pipe-grades-maintenance-for-longer-service-life","status":"publish","type":"news","link":"https:\/\/jiuguangmetal.com\/fr\/news\/stainless-steel-pipe-grades-maintenance-for-longer-service-life\/","title":{"rendered":"Stainless Steel Pipe Grades & Maintenance for Longer Service Life"},"content":{"rendered":"
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\"garde-corps<\/h1>\n

Stainless steel pipes are divided into decorative pip<\/span>es, fluid\u2011transfer pipes and industrial pipes. Different grades serve different purposes. Rusting is mostly caused by environment, chloride ions or surface damage, not necessarily poor material quality.<\/span><\/h1>\n<\/div>\n
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Common Stainless Steel Pipe Grades<\/h2>\n<\/div>\n
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201 (1Cr17Mn6Ni5N)<\/h3>\n<\/div>\n
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  • Composition: High manganese, low nickel<\/li>\n
  • Performance: Moderate rust resistance; poor chloride\u2011ion resistance. Prone to rust in humid, coastal or salty environments; low cost.<\/li>\n
  • Application: Indoor decorative pipes<\/strong> for railings, handrails and window trim. NOT for water or fluid conveyance<\/strong>. Not suitable for outdoor exposure.<\/li>\n<\/ul>\n<\/div>\n
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    Only for dry indoor use; surface rust will appear quickly outdoors.<\/div>\n<\/div>\n<\/blockquote>\n<\/div>\n
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    304 (06Cr19Ni10 \/ SUS304) \u2728 Most common for household use<\/h3>\n<\/div>\n
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    • Chromium ~18%, nickel ~8%, austenitic stainless steel; non\u2011magnetic or weakly magnetic.<\/li>\n
    • Performance: Resists normal moisture, weak acids and alkalis. Works for indoor and general outdoor conditions. Limited chloride\u2011ion resistance; pitting rust may occur under long\u2011term contact with salt\u2011water or seawater.<\/li>\n
    • Application: Thin\u2011wall domestic water pipes, outdoor railings, equipment pipelines, gas pipelines, water supply and drainage fittings.<\/li>\n<\/ul>\n<\/div>\n
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      304 is the mainstream grade for household stainless steel water pipes.<\/div>\n<\/div>\n<\/blockquote>\n<\/div>\n
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      316L (022Cr17Ni12Mo2 \/ SUS316L) \u2b50 Superior corrosion resistance<\/h3>\n<\/div>\n
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      • Molybdenum added; \u201cL\u201d stands for low carbon. Greatly improved resistance to chloride ions; withstands salt spray, seawater and chemicals.<\/li>\n
      • Performance: Far better anti\u2011rust performance than 304; excellent for coastal\/salty environments; reduced inter\u2011granular corrosion after welding.<\/li>\n
      • Application: Coastal projects, chemical pipelines, seawater equipment, high\u2011end drinking\u2011water pipes, swimming\u2011pool pipelines. Price is 30\u201160\u202f% higher than 304.<\/li>\n<\/ul>\n<\/div>\n
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        321 (06Cr18Ni11Ti)<\/h3>\n<\/div>\n
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        • Titanium\u2011stabilized grade; good high\u2011temperature performance, resists inter\u2011granular corrosion at high temperature.<\/li>\n
        • Application: High\u2011temperature boilers, heat\u2011exchanger tubes; rarely used in residential projects.<\/li>\n<\/ul>\n<\/div>\n
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          430 (Ferritic stainless steel)<\/h3>\n<\/div>\n
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          • Strong magnetic property, mediocre corrosion resistance. Mostly for decoration, seldom used as pressure\u2011bearing pipes.<\/li>\n<\/ul>\n<\/div>\n
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            Important misconceptions<\/div>\n<\/div>\n<\/blockquote>\n<\/div>\n
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            1. A magnet cannot judge quality<\/strong>: Cold\u2011bent 304 may become magnetic; 201 can be non\u2011magnetic. Do not test with magnets.<\/li>\n
            2. Meaning of \u201cL\u201d: Low carbon. 304L \/ 316L are preferred for welded pipes<\/strong> to lower post\u2011weld corrosion risk.<\/li>\n<\/ol>\n<\/div>\n
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              Pipe type notes<\/h3>\n<\/div>\n
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              1. Decorative pipe<\/strong>: Bright polished surface, thin wall, low pressure resistance. Only for railings & handrails; do NOT use for water supply<\/strong>.<\/li>\n
              2. Industrial fluid \/ thin\u2011wall water\u2011supply pipe<\/strong>: Smooth inner wall, uniform wall thickness, meets pressure standards, for water and media transport.<\/li>\n<\/ol>\n<\/div>\n
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                Grade Selection Guide<\/h3>\n<\/div>\n
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                \u8868\u683c<\/div>\n
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                <\/div>\n
                <\/div>\n
                <\/div>\n<\/div>\n<\/div>\n
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                \n\n\n\n\n\n\n\n\n
                Sc\u00e9nario<\/th>\nNiveau recommand\u00e9<\/th>\nNot Recommended<\/th>\n<\/tr>\n<\/thead>\n
                Indoor domestic water pipes & handrails<\/td>\n304<\/td>\n201 (never for water pipes)<\/td>\n<\/tr>\n
                General outdoor railings<\/td>\n304<\/td>\n201 (rusts within 1\u20113 years)<\/td>\n<\/tr>\n
                Seaside, salt\u2011spray, swimming pool, chemical service<\/td>\n316L<\/td>\n304 (subject to pitting corrosion)<\/td>\n<\/tr>\n
                High\u2011temperature process piping<\/td>\n321 \/ 316L<\/td>\n201, standard 304<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n
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                Maintenance Tips to Extend Service Life<\/h2>\n<\/div>\n
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                Stainless steel relies on a passive chromium\u2011oxide surface film for corrosion resistance. Damage to this film leads to rust. Maintenance aims to protect this passive film.<\/div>\n<\/div>\n
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                \u2705 Good Practices<\/h3>\n<\/div>\n
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                1. \n
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                  Remove salt deposits, dust, cement and mortar timely<\/p>\n

                  <\/div>\n

                  Salt spray (coastal areas), cement and lime residues accelerate pitting corrosion. Rinse surfaces promptly. Clean sheltered corners where rain cannot reach.<\/p>\n<\/div>\n<\/div>\n<\/li>\n

                2. \n
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                  Cleaning: Use water plus neutral detergent with soft cloth or sponge.<\/p>\n

                  <\/div>\n

                  After cleaning, wipe off standing water<\/strong>. Avoid trapped water on pipe surfaces, gaps and welds \u2014 welds are high\u2011risk corrosion zones.<\/p>\n<\/div>\n<\/div>\n<\/li>\n

                3. \n
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                  Special care for welds<\/p>\n

                  <\/div>\n

                  Remove welding slag and oxide scale after welding. For outdoor \/ coastal installations, apply dedicated stainless\u2011steel protective wax if possible.<\/p>\n<\/div>\n<\/div>\n<\/li>\n

                4. \n
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                  For potable\u2011water stainless\u2011steel pipes<\/p>\n

                  <\/div>\n

                  If local water has high chloride content (groundwater, coastal tap water), select 316L. Avoid long\u2011term stagnant water; run taps periodically.<\/p>\n<\/div>\n<\/div>\n<\/li>\n<\/ol>\n<\/div>\n

                  \n

                  \u274c Things You Must Avoid (cause rapid corrosion)<\/h3>\n<\/div>\n
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                  1. Do not use steel wool or steel wire brushes. They scratch the passive film; scratches trap dirt and speed up pitting. For stubborn stains use soft white scouring pads only.<\/li>\n
                  2. Avoid bleach, chlorine\u2011containing disinfectants and chlorine\u2011based cleaners. Chloride ions destroy the passive oxide layer and cause rust spots.<\/li>\n
                  3. Do not leave salty, acidic or chemical residues sitting on pipe surfaces for long periods.<\/li>\n
                  4. Prevent prolonged contact with cement, plaster and salty soil.<\/li>\n<\/ol>\n<\/div>\n
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                    Once deep pitting corrosion occurs, damage to the passive layer is permanent and cannot be fully repaired by cleaning alone.<\/div>\n<\/div>\n<\/blockquote>\n<\/div>","protected":false},"excerpt":{"rendered":"

                    Stainless steel pipes are divided into decorative pipes, fluid\u2011transfer pipes and industrial pipes. Different grades serve different purposes. Rusting is mostly caused by environment, chloride ions or surface damage, not necessarily poor material quality. Common Stainless Steel Pipe Grades 201 (1Cr17Mn6Ni5N) Composition: High manganese, low nickel Performance: Moderate rust resistance; poor chloride\u2011ion resistance. Prone to […]<\/p>\n","protected":false},"featured_media":0,"comment_status":"open","ping_status":"closed","template":"","class_list":["post-14134","news","type-news","status-publish","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/jiuguangmetal.com\/fr\/wp-json\/wp\/v2\/news\/14134","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jiuguangmetal.com\/fr\/wp-json\/wp\/v2\/news"}],"about":[{"href":"https:\/\/jiuguangmetal.com\/fr\/wp-json\/wp\/v2\/types\/news"}],"replies":[{"embeddable":true,"href":"https:\/\/jiuguangmetal.com\/fr\/wp-json\/wp\/v2\/comments?post=14134"}],"wp:attachment":[{"href":"https:\/\/jiuguangmetal.com\/fr\/wp-json\/wp\/v2\/media?parent=14134"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}