Key Requirements for Steel Pipes in The Chemical Industry

Requirement Category                                Details

Corrosion Resistance                                        Resistance to uniform corrosion, pitting, crevice corrosion, and stress                                                                                            corrosion cracking (SCC)

Material Purity                                                     Low S, P, O, N content; controlled inclusions to prevent intergranular corrosion

Microstructural Stability                                 Austenitic/duplex steels must avoid σ-phase precipitation for long-term safety

Non-Destructive Testing                                 100% eddy current, ultrasonic, radiographic inspection; critical components

                                                                         tested individually

Weldability                                                         Weld joints must match base metal in strength and corrosion resistance;                                                                                     post-weld heat treatment to prevent sensitization

Dimensional & Surface Quality                      Tight inner diameter tolerance, internal surface finish Ra ≤ 0.8μm to minimize

                                                                          fluid retention

Hebei K-Steel Pipe Industry can supply all kinds of steel pipe

ASTM A312 / ASME SA312‌ (Seamless and Welded Austenitic Stainless Steel Pipes)

‌Application‌: Transport of highly corrosive media such as acids, alkalis, and salt solutions.

‌Common Grades‌:

‌TP304/TP304L‌: General-purpose stainless steel with good corrosion resistance

‌TP316/TP316L‌: Molybdenum-containing (2–3%), excellent resistance to chloride-induced stress corrosion cracking, commonly used in marine or chlorinated environments

‌TP321/TP347‌: Stabilized stainless steels with niobium/tantalum, resistant to intergranular corrosion at high temperatures

‌Features‌: High purity, solution annealed, 100% eddy current + ultrasonic testing.

ASTM A790 / ASME SA790‌ (Ferritic-Austenitic Duplex Stainless Steel Pipes)

‌Application‌: High-chloride environments such as seawater cooling systems and desulfurization units.

‌Typical Materials‌:

‌UNS S31803 (2205)‌: Cr 22%, Ni 5%, Mo 3%, strength twice that of 316L, excellent pitting and stress corrosion resistance

‌UNS S32750 (2507)‌: Super duplex steel for extreme corrosion conditions

‌Requirements‌: Ferrite content must be controlled between 35%–55% to ensure phase balance.

GB/T 14976-2023‌ (Seamless Stainless Steel Tubes for Fluid Transmission)

‌Application‌: Chemical, pharmaceutical, and food industries in China.

‌Typical Materials‌:

‌06Cr19Ni10 (304L)‌: Low-carbon austenitic steel to prevent intergranular corrosion

‌06Cr17Ni12Mo2 (316L)‌: High corrosion resistance, suitable for chlorinated media

‌Requirements‌: Implemented since 2024, with stricter controls on surface quality, dimensional accuracy, and NDT.

ASTM A688 / ASME SA688‌ (Welded Austenitic Stainless Steel Tubing for Feedwater Heaters)

‌Application‌: Heat exchangers and condensers in chemical plants.

‌Materials‌: TP304, TP316; must undergo solution annealing after welding

‌Advantages‌: Lower cost than seamless, performance close, widely used in medium-pressure heat exchangers.

‌Nickel-Based Alloy Tubes (e.g., Inconel 625, Hastelloy C-276)‌

‌Application‌: Strong oxidizing acids, mixed acids, high-temperature/high-pressure corrosive environments.

‌Typical Materials‌:

‌Inconel 625 (UNS N06625)‌: Ni-Cr-Mo-Nb alloy, resistant to nitric, hydrochloric, and phosphoric acids

‌Hastelloy C-276 (UNS N10276)‌: Exceptional resistance to localized corrosion, suitable for wet chlorine, hypochlorite environments

‌Standards‌: ASTM B691, B564, B775

‌Features‌: High cost, but irreplaceable in extreme conditions.