TA1, TA2, TA9: A Clear Guide to Selecting Titanium Materials for Chlor‑Alkali Pumps and Valves

In the highly corrosive environment of the chlor‑alkali industry, the reliability of pumps, valves, and piping directly determines production safety and efficiency. Titanium, with its unparalleled resistance to chloride‑induced corrosion, has become an indispensable material.

However, faced with different titanium grades such as TA1, TA2, and TA9, many engineers and procurement professionals struggle with the choice. What are the differences? Which one should be used for a given service condition?

This guide will help clarify the three most common titanium grades for chlor‑alkali equipment selection.

PART 01 – Common Advantages: Why Titanium is Preferred in Chlor‑Alkali

TA1, TA2, and TA9 are all commercially pure titanium or titanium‑palladium alloys, sharing the core benefits of titanium:

• Excellent corrosion resistance – In oxidizing media (e.g., wet chlorine, hypochlorite in chlor‑alkali production), titanium forms a dense, stable oxide film. It resists pitting, crevice corrosion, and stress corrosion caused by chlorides – capabilities that stainless steel cannot match.

• High strength – Strength close to that of ordinary steel, but density only 60% of steel, effectively reducing equipment weight.

• Good workability – Excellent forging, machining, and welding properties.

PART 02 – Individual Characteristics: The Performance Pyramid

TA1, TA2, and TA9 can be viewed as a performance and cost pyramid.

TA1 (Grade 1) – Economical choice with excellent plasticity

• Key characteristics: Lowest impurity content (oxygen, iron) among commercially pure titanium grades, giving the best plasticity, toughness, and cold formability, but the lowest strength.

• Key data: Tensile strength ≥ 240 MPa.

• Applicable conditions: Normal pressure or low‑pressure environments with operating temperatures not exceeding 80°C. Less aggressive media such as dilute alkali or brine in storage tanks and heat exchanger tubes.

• Recommendation: TA1 is the first choice for complex shapes requiring deep cold stamping. However, for pressure‑bearing pump and valve flanges, its strength must be carefully evaluated.

TA2 (Grade 2) – The golden balance of strength and corrosion resistance

• Key characteristics: The most commonly used and best‑balanced commercially pure titanium grade. It achieves an ideal balance of strength, plasticity, and corrosion resistance – known as "standard pure titanium."

• Key data: Tensile strength ≥ 400 MPa. This is the specified material for most standard titanium flanges and fittings.

• Applicable conditions: Most chlor‑alkali processes from ambient to medium temperature (~150°C). Flanges, pump casings, and valve bodies in brine sections, electrolyte lines, and wet chlorine piping.

• Recommendation: TA2 is the workhorse and default option for chlor‑alkali pump and valve flanges. Unless special conditions apply, TA2 is a safe choice both in performance and economy.

TA9 (Grade 7) – The ultimate solution for severe conditions

• Key characteristics: Approximately 0.12–0.25% palladium (Pd) added to TA2. This small amount of noble metal significantly improves corrosion resistance, especially in reducing media and against crevice corrosion.

• Key data: Mechanical properties similar to TA2, but corrosion resistance improved by orders of magnitude.

• Applicable conditions: High temperature, high concentration, acidic, or reducing media. Areas with dead zones or crevices (e.g., flange gaskets) prone to crevice corrosion. Critical equipment where media composition is complex or variable, requiring maximum reliability.

• Recommendation: TA9 is the choice for the most extreme and severe conditions. It provides the highest safety margin. Although initial cost is higher, the value of maintenance‑free and replacement‑free operation over the equipment lifecycle is immeasurable.

Conclusion

On the complex battlefield of the chlor‑alkali industry, there is no universal material – only the most suitable solution. TA1, TA2, and TA9 form a complete material system covering conditions from routine to extreme.

We provide high‑quality TA1, TA2, and TA9 titanium flanges meeting ASTM, ASME, and GB standards, and are committed to being a reliable partner in equipment material selection – laying the strongest material foundation for the safe, efficient, and long‑life operation of the chlor‑alkali industry.