What Chemicals Can GR2 Titanium Withstand? Understand Its Anti-Corrosion Superpower

In industries such as chemical engineering, ocean engineering and chlor-alkali industry, corrosion is one of the most troublesome challenges for equipment material selection. Gr2 Titanium (domestic equivalent grade TA2) is hailed as the "anti-corrosion champion" among commercially pure titanium thanks to its outstanding corrosion resistance. So what chemicals can GR2 resist? What are its forbidden service environments? This article delivers a comprehensive analysis.

I. The Secret to Corrosion Resistance: A Dense Oxide Film

The core reason for GR2 Titanium’s corrosion resistance is that a dense and stable titanium dioxide (TiO₂) oxide film instantly forms on its surface. This film can rapidly self-repair even after damage, isolating the base material from corrosive media. This property enables GR2 to perform excellently in neutral and oxidizing environments.

II. Chemical Resistance Table for GR2 Titanium

III. Three Categories of Media: Tolerable, Use with Caution, Prohibited

1. Media with Stable Resistance

These environments represent advantageous working conditions for GR2 Titanium Materials and witness the widest industrial applications:

• Chloride systems: seawater, sodium chloride, potassium chloride solutions, hypochlorites, wet chlorine gas;
• Oxidizing inorganic acids: medium and low-concentration nitric acid;
• Most organic acids: acetic acid, citric acid, lactic acid, stearic acid, etc.;
• Neutral and weakly alkaline salt solutions;
• Hydrocarbons and organic solvents, such as ethanol and benzene.

In seawater desalination, chlor-alkali chemical industry, pharmaceutical clean transportation, flue gas desulfurization and other projects, GR2 Titanium Plates, titanium tubes and titanium bars are widely adopted. The service life of equipment can reach more than 20–25 years, far exceeding stainless steel materials.

2. Media Requiring Thorough Evaluation; Not to Be Adopted Directly

GR2 cannot be arbitrarily used in such environments. Rising temperature, deoxygenated solution and local crevices will bring corrosion risks:

(1). Dilute reducing acids: dilute hydrochloric acid and dilute sulfuric acid. A passive film can be maintained at ambient temperature if the solution contains a certain amount of oxygen, ferric ions and other oxidants; once the solution becomes deoxygenated, corrosion speeds up rapidly. If such working conditions are unavoidable in production, upgrading to GR7 (Ti‑0.2Pd) titanium material is recommended.

(2). High-temperature concentrated alkaline solutions: dilute alkali at room temperature exerts minor impact on titanium materials; when the temperature exceeds 120°C with high alkali concentration, hydrogen embrittlement will occur, leading to brittle fracture of materials.

(3). High-temperature high-concentration chloride environments with crevices: crevices at flange gaskets and sediment accumulation areas cause crevice corrosion. For chloride service above 75°C, structural design should eliminate narrow crevices as much as possible; GR12 titanium alloy can be adopted when necessary.

3. Strictly Prohibited Media

GR2 titanium is unsuitable for the following media regardless of temperature:

(1). Hydrofluoric acid and low-pH systems containing fluoride ions; fluoride ions directly dissolve the titanium oxide film;

(2). Dry chlorine gas, which can react violently with titanium with combustion risks;

(3). High-temperature high-concentration reducing acids, such as hot hydrochloric acid above 20% and high-temperature concentrated sulfuric acid;

(4). Red fuming nitric acid with spontaneous combustion risks; direct application of GR2 titanium is strictly forbidden in engineering.

IV. Typical Applications of GR2 across Industries

• Chlor-alkali Industry: Anode plates for electrolytic cells, chlorine gas coolers, etc. Resists corrosion from wet chlorine gas; service life is 5–10 times that of 316L stainless steel.
• Seawater Desalination: Evaporator plates, seawater pipelines, with annual corrosion rate ≤02 mm/a, achieving nearly zero corrosion.
• Chemical Equipment: Nitric acid storage tanks, acetic acid reactors, resistant to multiple organic acids and oxidizing acids.
• PTA Production: Linings for oxidation reactors, resisting corrosion from bromide and acetic acid.

FAQ

Q1: Which offers better corrosion resistance, GR2 or 316L stainless steel?

A: In oxidizing media such as seawater, wet chlorine gas and nitric acid, GR2 boasts far superior corrosion resistance to 316L stainless steel. For instance, in 98% sulfuric acid at 80°C, the corrosion rate of TA2 (GR2) is only 0.001 mm/a, while that of 316L stainless steel exceeds 10 mm/a.

Q2: Can GR2 be used under high temperatures?

A: The recommended long-term service temperature for GR2 is ≤150°C, with short-term tolerance up to 300°C. Higher temperature accelerates corrosion; every 10°C temperature rise may increase the corrosion rate by 10%–20%.

Q3: Is GR2 completely unusable in hydrochloric acid and sulfuric acid?

A: It cannot be generalized. GR2 possesses certain resistance in dilute sulfuric acid (<5%) and dilute hydrochloric acid (<10%). However, corrosion accelerates sharply with increased concentration. Under such circumstances, grades including Gr.7 (palladium-containing) or Gr.12 (molybdenum and nickel-containing) are recommended.

Q4: How does GR2 perform in alkaline environments?

A: It delivers good corrosion resistance against most room-temperature alkaline solutions (such as saturated calcium hydroxide and magnesium hydroxide solutions). Nevertheless, boiling NaOH solution causes severe corrosion to GR2 and must be avoided.

Q5: Are there corrosion resistance differences between GR2 and GR1?

A: Their corrosion resistance is nearly equivalent, yet GR2 features higher strength, making it the most widely applied grade in industry.

Conclusion

With outstanding corrosion resistance, GR2 Titanium (TA2) performs excellently in seawater, wet chlorine gas, nitric acid, organic acids and most alkaline solutions, serving as an ideal material choice for chemical, marine, chlor-alkali and other industries. However, thorough evaluation or special alloy grades are required for extreme media such as concentrated sulfuric acid, concentrated hydrochloric acid, hydrofluoric acid and boiling concentrated alkali.

ProX Metal supplies a full range of titanium grades including GR1, GR2 and GR5, with complete specifications for plates, foils, tubes and bars manufactured in strict compliance with relevant standards. We possess extensive experience in material selection for chemical anti-corrosion projects and can provide corrosion assessment and grade selection suggestions based on service media conditions. We deliver stable and customized processing services of compliant GR2 titanium materials for customers in fine chemical and chlor-alkali sectors, helping enterprises avoid material selection errors and guarantee long-term stable operation of equipment.