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SS 316 and Aqua Regia: Chemical Resistance

Stainless steel 1.4401 (AISI 316)

Rating

Concentration20 °C50 °CRemark
concentration not statedDD

Material comparison at 20 °C

Aqua Regia: Material comparison at 20 °CSS 316: D (highlighted); ECTFE/ETFE: A; PTFE: A; FEP: B; PMP: C; PVDF: C.ECTFE/ETFE: APTFE: AFEP: BPMP: CPVDF: CSAN: CAluminium: DEPDM: DViton (FPM): DHDPE: DLDPE: DNBR: DNylon (PA): DPolycarbonate: DPETG: DAcetal (POM): DPP: DPolystyrene: DPolysulfone: DPVC Rigid: DPVC Flexible: DSS 304: DSS 316: D316Silicone: –
A very good resistanceB good resistanceC limited resistanceD not resistantno data
Each bar is one material. Taller bars indicate better resistance. The highlighted bar is the current material.

Resistance overview

SS 316 is not resistant (D) to Aqua Regia and should not be used in direct contact. The chemical is expected to cause rapid degradation, which can include dissolution, cracking, severe swelling, or complete structural failure of the material.

Application context

Aqua Regia is commonly encountered in surface cleaning and water treatment. SS 316 (Stainless steel 1.4401 (AISI 316)) is a metal typically used for vessels, heat exchangers, fittings and structural components. Because Aqua Regia is classified as corrosive, the choice of containment material is especially critical to prevent leaks, equipment damage, and safety hazards.

Practical recommendation

SS 316 is not recommended for use with Aqua Regia. The D rating indicates that the material will suffer rapid and severe degradation, which may include cracking, dissolution, severe swelling, or complete structural failure. Using this combination risks equipment damage, leaks, and potential safety incidents. Consider using ECTFE/ETFE, PTFE instead, which are rated A for this chemical and offer reliable long-term performance.

Did you know?

Stainless steel 1.4401 (AISI 316) is commonly chosen for vessels, heat exchangers, fittings and structural components because of its combination of chemical resistance, mechanical strength, and cost-effectiveness.

Materials rated A or B at 20 °C

Fluoropolymers
PTFE A, FEP B, ECTFE/ETFE A

About SS 316

Stainless steel 316 (1.4401) contains molybdenum, which improves resistance to chlorides over 304. Hydrochloric acid and other halide acids still cause pitting.

Rating scale

A rating marked * is an estimate in the source, not a test result. An estimate is given as one value without a temperature.

About this data

The ratings come from the chemical resistance list published by Bürkle GmbH, which compiled them from raw-material manufacturers’ data. They describe laboratory tests on the raw material at 20 °C and 50 °C.

A finished part also sees pressure, mechanical stress, welds and mixtures that a laboratory test does not. Treat the rating as a first filter and test under your own conditions before relying on it.