Which industrial titanium plate model is best suited to alkali-resistant chemical reactors?
In scenarios involving strong alkaline corrosion, such as in the chlor-alkali chemical industry and fertiliser production, Industrial Titanium Plates have become the material of choice for manufacturing reactors thanks to their unparalleled corrosion resistance. So, which model of industrial titanium plate should be chosen for alkali-resistant chemical reactors? This article focuses on the widely used GR2 titanium plate (national standard TA2/US standard Gr2), analysing its technical details in actual production.
I. Microscopic Mechanism of Alkali Corrosion Resistance
The GR2 titanium plate forms a dense passive film (TiO₂) on its surface in alkaline environments. This film has the following characteristics:
Dynamic self-repairing ability: When the local film is damaged by mechanical abrasion, titanium elements recombine with oxygen atoms in the medium to form a new film, thereby preventing the base material from being penetrated by alkali.
High-temperature stability: In concentrated alkaline solutions (such as 50% NaOH), the annual corrosion rate is less than 0.01 mm at temperatures of up to 350 °C. This is far superior to stainless steels such as 316L, which have a corrosion rate exceeding 1 mm per year.
II. Key process performance and engineering compatibility
Welding reliability:
When using automatic TIG welding, the strength of the weld joint is ≥90% of that of the base material. The heat-affected zone does not exhibit any tendency towards intergranular corrosion, ensuring the long-term sealing of reactor welds in an 80 °C alkali solution.
Forming and processing control:
Cold-rolled thin plates (0.3–4 mm): These are used to make reactor liners, for which the rolling deformation rate must be kept below 30% to prevent stress corrosion.
Hot-rolled thick plates (4–30 mm): These are used for pressure vessel shells and require vacuum annealing at 850°C to eliminate residual stresses and ensure dimensional stability.
III. Typical application scenarios and economic benefits
Chlor-alkali industry electrolyser:
GR2 titanium anode plates have a service life of over eight years in saturated brine. This improves maintenance cycles threefold compared to graphite electrodes and reduces downtime losses.
Urea synthesis tower internal components
In environments containing ammonium carbamate at 200°C and 15 MPa, GR2 baffles have an annual corrosion rate of only 0.005 mm. This extends the life of the equipment to 20 years.
IV. Material selection considerations
Impurity element control:
The iron (Fe) content must be less than 0.3%, otherwise pitting may occur in high-temperature alkali solutions. According to ASTM B265 standards, GR2 grade titanium plates are recommended.
Surface treatment requirements:
The surface in contact with the medium must undergo sandblasting (Sa2.5 grade) and acid-washing passivation to improve film-layer uniformity and reduce the risk of crevice corrosion.
Thanks to material purity control (titanium content ≥99.2%), the passive film protection mechanism, and customised processing techniques (e.g. the provision of flaw-detection grade titanium plates by Baoji enterprises), industrial GR2 titanium plates are the key to the technical success of alkali-resistant reactors. For corrosion data charts of GR2 titanium plates in specific media (e.g. KOH/NaOH concentration-temperature curves), please refer to professional supplier test reports. If you would like more detailed information about industrial titanium plates, please fill out the form and we will contact you promptly!