Standards for Grade 5 Titanium Alloy (Ti‑6Al‑4V)
Grade 5 titanium alloy, universally recognized as Ti‑6Al‑4V, is the most widely used α+β titanium alloy globally. It has well‑established equivalents in Chinese national standards, U.S. standards, ASTM specifications, and dedicated military and aerospace standards, forming a comprehensive standard system that supports its application across industries.
1. Chinese National Standard (GB/T)
In China, Grade 5 titanium alloy corresponds to the TC4 alloy designation. The primary national standards governing TC4 are:
GB/T 3620.1‑2016: Titanium and titanium alloys-Part 1: Composition limits. This standard defines the chemical composition of TC4, matching Grade 5's nominal 6% Al, 4% V, and strict impurity controls (Fe ≤ 0.30%, O ≤ 0.20%, N ≤ 0.05%, C ≤ 0.08%, H ≤ 0.0125%).
GB/T 2965‑2020: Titanium and titanium alloy bars, rods and wires. It specifies the mechanical properties, dimensions, tolerances, and testing methods for TC4 bars, equivalent to ASTM B348 for bar products.
GB/T 3621‑2007: Titanium and titanium alloy plates, sheets and strips, applicable to TC4 plate and sheet products.
2. U.S. and ASTM Standards
In the U.S. system, Grade 5 is the official designation, with key standards:
ASTM B265: Standard Specification for Titanium and Titanium Alloy Strip, Sheet, and Plate. Governs Grade 5 sheet, plate, and strip products, covering chemical composition, mechanical properties, and quality requirements.
ASTM B348: Standard Specification for Titanium and Titanium Alloy Bars and Billets. The core standard for Grade 5 bars and billets, widely referenced globally for its precise compositional and mechanical benchmarks.
UNS R56400: The Unified Numbering System designation for Grade 5 (Ti‑6Al‑4V), ensuring consistent material identification across U.S. standards.
ASME SB348: The ASME equivalent of ASTM B348, used in pressure vessel and boiler applications.
3. Military and Aerospace Standards
Grade 5 has extensive coverage in military and aerospace specifications, critical for high‑reliability applications:
AMS 4928: The premier aerospace material specification for Ti‑6Al‑4V bars, forgings, and rings. It imposes stringent controls on chemistry, microstructure, mechanical properties, and non‑destructive testing (NDT), mandatory for aircraft structural components, engine parts, and landing gear.
AMS 4911, AMS 4965, AMS 4967: Complementary aerospace standards for specific product forms (e.g., forgings, fasteners) and heat‑treated conditions of Grade 5.
MIL‑T‑9047: U.S. military standard for titanium and titanium alloy bars, shapes, and forgings, enforcing rigorous quality assurance for military hardware.
MIL‑STD‑2154: Military standard outlining inspection and testing requirements for titanium alloys, ensuring Grade 5 meets defense‑sector performance demands.
Chinese aviation standard HB 7716‑2002: Aerospace titanium alloy bar specification, tailored for domestic aircraft applications, aligning with AMS 4928 requirements.
These standards confirm Grade 5's status as a fully qualified material for the most demanding military and aerospace environments. Its standardization across global frameworks ensures interchangeability, reliability, and compliance in critical structural applications.
