How Titanium Sponge and Scrap Becomes the Final Product

Titanium is renowned for its strength, exceptional corrosion resistance, and lightweight properties, making it an invaluable material across various sectors, particularly in aerospace, medical, and chemical processing. But how does titanium transition from raw materials like titanium sponge and scrap into usable plates, sheets, and bars? This guide will take you through how scrap and sponge are transformed into a final product.

Vacuum Arc Remelting

In the vacuum arc remelt (VAR) process, a cylindrical consumable electrode—made from titanium sponge, alloying additions, and/or certified revert scrap—is melted by an electric arc in a vacuum chamber. The molten titanium pool solidifies in a water-cooled copper crucible, producing a dense, high-purity ingot.

Electrode preparation is meticulously controlled. Sponge and alloying elements are compressed into compacts or briquettes, which are subsequently welded, typically using Gas Metal Arc Welding (GMAW), to create electrodes up to 15 feet long. Clean, traceable revert titanium may be blended in to reduce costs while still meeting quality standards.

For critical applications, the industry practice typically involves one of two methods: a double consumable-electrode VAR process, where the first melt consolidates the feedstock into a primary ingot and the second melt enhances the chemistry and soundness; or hearth melting followed by VAR.

Hearth Melting
Electron beam melting (EBM) and other hearth melting technologies are primarily used to process high scrap content and produce slab and ingot directly. Hearth melting techniques employ an electron beam or plasma arc to melt material on a separate, refractory-less hearth before the molten metal flows into a slab or ingot mold. This process produces slabs and ingots with uniform composition and near-complete elimination of high-density inclusions, making it especially effective for unalloyed and low-alloy titanium grades. While these methods enable efficient scrap utilization, continuous alloy addition, and direct slab and ingot production, aerospace-grade titanium still requires VAR as the final melt stage to meet quality requirements.

Hearth melting offers several advantages in efficiency and quality compared to VAR. One key benefit is the deep settling pool in the hearth, which effectively removes high- and low-density tramp materials, such as tungsten from welding residues, before the melt enters the ingot mold. Additionally, the continuous addition of sponge, scrap, or master alloys allows for real-time adjustments to the chemical composition, ensuring consistent product quality in a single melting operation. By producing rectangular slabs weighing between 40,000 and 50,000 pounds, manufacturers can deliver the material directly to the hot rolling mill, eliminating the need for breakdown steps, reheating cycles, and additional surface conditioning. As a result, overall productivity is significantly enhanced while material and energy costs are reduced.