What Is Explosive Welding For Titanium Tube-Sheet?

In highly corrosive working conditions such as chlor‑alkali industry, seawater desalination, marine engineering and new‑energy hydrometallurgy, titanium‑steel composite tube‑sheets serve as the core components of shell‑and‑tube heat exchangers. They combine the corrosion resistance of titanium with the high-pressure bearing capacity of carbon‑steel or stainless‑steel substrates.

1.Fully Titanium Tube‑Sheet

Made entirely of titanium, it delivers good corrosion resistance. Nevertheless, titanium material is costly, and large‑size thick plates incur extremely high expenses, limiting its large‑scale application in major projects.

2.Titanium‑Surfaced Tube‑Sheet

A carbon‑steel base is surfaced with a titanium anti‑corrosion layer. Welding titanium to steel readily produces brittle FeTi phases, giving rise to defects including pores, cracks and delamination. When working pressure and temperature fluctuate, the surfacing layer tends to peel off. Large‑area surfacing requires long construction cycles and is difficult to repair, bringing leakage risks to heat exchangers.

3.Mechanical Expansion Joint

Titanium tubes are mechanically joined to the tube‑sheet via interference fit without metallurgical fusion. Process media can penetrate into gaps, triggering crevice corrosion in chloride‑ion and wet‑chlorine environments, which shortens equipment service life and makes it unsuitable for harsh working conditions.

1.Process Property

Solid‑state pressure welding; the plates are not melted as a whole.

2.Key Procedures

‑ A preset gap is reserved between the titanium cladding layer and the carbon‑steel/stainless‑steel substrate, followed by degreasing and abrasive cleaning for surface purification.
‑ Explosives are arranged on the titanium plate surface. Detonation by detonators drives the titanium plate to strike the substrate at high speed via detonation shock waves.
‑ Ultra‑high pressure generated by impact breaks oxide films and produces metal jets, realizing atomic‑level metallurgical bonding. A wavy bonding interface is formed to produce titanium‑steel composite blanks.
‑ Subsequent heat treatment, levelling, precision machining and drilling convert the blanks into finished titanium‑steel composite tube‑sheets.

3.Core Advantages

‑ Avoids brittle‑phase formation caused by fusion welding between titanium and steel.
‑ Interfacial shear strength exceeds that of base metals, delivering excellent anti‑delamination performance and resistance to temperature cycling.
‑ Enables manufacture of large‑diameter and thick tube‑sheets for large‑size heat‑exchanger requirements.

1.High‑Strength Metallurgical Bonding of Dissimilar Metals

Atomic‑level metallurgical bonding is achieved between titanium and carbon‑steel / stainless‑steel, rather than simple mechanical attachment. Full‑coverage ultrasonic testing (UT) is performed to ensure bonding ratio complies with pressure‑vessel standards. Delamination and peeling rarely occur under alternating temperature and pressure, lowering risks of tube‑sheet corrosion‑induced leakage.

2.Balanced Corrosion Resistance and Cost‑effectiveness

Gr1/Gr2/Gr12‑grade titanium is adopted for the cladding layer to resist strongly corrosive media such as seawater, wet chlorine, chlorate salts and dilute acids. The pressure‑vessel‑grade carbon‑steel or stainless‑steel substrate bears structural loads. Compared with fully titanium tube‑sheets, it retains anti‑corrosion performance while substantially cutting costs for superior cost‑performance.

3.Capable of Large‑size Fabrication with Good Machinability

Large‑diameter thick composite tube‑sheet blanks can be manufactured. Composite plates support CNC drilling and milling to adapt to dense tube holes and diverse hole layouts of heat exchangers. Interfacial cracking and delamination seldom occur during machining, satisfying pressure‑vessel manufacturing specifications.

4.Wide Working‑condition Adaptability and Extended Equipment Service Life

Suitable for heat‑exchange equipment in chlor‑alkali plants, seawater desalination facilities and offshore platforms, with good resistance to pitting and crevice corrosion. Compared with stainless‑steel and titanium‑surfaced structures, it greatly prolongs equipment service life, reduces shutdown‑maintenance frequency and cuts operation‑and‑maintenance costs.

1.High Sensitivity to Process Parameters

Deviations in any parameter including explosive formulation, detonation velocity, inter‑plate gap, surface treatment and initiation mode will reduce finished‑product rate.
‑ Abnormal explosive parameters: plate cracking, titanium‑layer burn‑off or local non‑bonding.
‑ Improper surface treatment: residual oil stains and oxide scales cause local interfacial debonding.
‑ Out‑of‑control heat‑treatment temperature: high temperatures facilitate the generation of brittle intermetallic compounds and degrade interfacial strength; annealing temperature must be strictly controlled.

2.Mandatory Quality‑control Procedures for Finished Products

For blanks intended for pressure‑vessel heat exchangers, a full set of inspections must be completed prior to mechanical processing:
‑ Ultrasonic testing to determine bonded area;
‑ Mechanical shear‑strength testing;
‑ Metallographic interface analysis to confirm absence of non‑bonded zones and massive brittle phases.

1.Chlor‑alkali Industry

wet‑chlorine coolers and brine heat exchangers. Resists corrosion by chloride ions and chlorine, serving as key equipment for chlor‑alkali production.

2.Seawater Desalination and Marine Engineering

seawater heat exchangers and condensers, resisting chloride‑ion corrosion from seawater.

3.Petrochemical and Fine‑chemical Industry

heat‑exchange equipment for salt‑solution and organic‑acid working conditions.

4.New‑energy and Hydrometallurgy

heat‑exchange and cooling equipment for high‑salt corrosive media.

5.Power and Nuclear Auxiliary Equipment

large‑size shell‑and‑tube heat exchangers for severely corrosive environments.

Ruihang is a direct manufacturer of titanium products, supplying optimal quality raw materials for your precision components. For more details, please feel free to contact us via email: Sam.Rui@bjrh-titanium.com