Material Basics Titanium Specifications: A Guide to Standards for Titanium and Titanium Alloys 3 min read • Updated September 2026 Titanium specifications define the properties of pure titanium and titanium alloys, providing the framework engineers use to select and qualify materials for demanding applications.Thanks to the allotropic behavior of titanium, which allows diverse changes in its microstructure, a broad range of properties and applications can be served with a relatively limited number of titanium alloy grades. Key US Titanium Specifications and the UNS System Many titanium alloys are produced to meet specifications established by the American Society for Testing and Materials (ASTM), aerospace titanium specifications (SAE-AMS), military specifications for titanium alloys (MIL-T), and titanium specifications developed by the American Society of Mechanical Engineers (ASME). These diverse US systems of titanium specifications are harmonized through the Unified Numbering System (UNS), which assigns metals and alloys a lettered prefix and a five-digit number. Titanium and its alloys fall within the UNS R5 category and carry designations such as UNS R50400. Table 1. Overview of Major Titanium Specification Systems Standard / Specification Organization Primary Scope Typical Use ASTM ASTM International Material specifications and test methods General industrial titanium products SAE AMS SAE International Aerospace material specifications Aerospace components MIL-T U.S. Department of Defense Military material specifications Defense and military applications ASME ASME Pressure equipment and mechanical engineering standards Boilers, pressure vessels, piping UNS Unified Numbering System Unified alloy designation system Cross-referencing titanium alloys ISO International Organization for Standardization International standards Global engineering applications EN (Euronorm) European Committee for Standardization (CEN) European material standards European manufacturing JIS Japanese Industrial Standards National material standards Japanese industry GOST Russian standards system National material standards Russian industry International Titanium Specifications Important international titanium specifications include ISO, Euronorm, the Russian GOST, and the Japanese JIS. Although these standard specifications overlap in many areas, they are not interchangeable. In an effort to achieve a more global approach, the Japanese Titanium Society has proposed unified systems of titanium specifications. The Challenge of Non-Standardized Titanium Specifications The primary challenge with titanium specifications is not a shortage of standard specifications defined by standards development organizations (SDOs). Instead, it is the proliferation of detailed, individual titanium specifications developed by aerospace companies, which often involve relatively limited production runs. Each aerospace company maintains its own specifications for titanium alloys, and these frequently require specific, proprietary process routes. As a result, many titanium specifications are in circulation that are relevant to, and understood by, only a select group of participants. In other words, a large number of titanium specs are not standardized.