How to tell if a screw is made of titanium!

To determine if a screw is made of titanium, verify it through physical properties, simple tests, and professional methods. The specific steps are as follows:

I. Judging the Basic Physical Characteristics

Density and Weight Titanium has a density of approximately 4.51g/cm³, which is only 56% of stainless steel's (about 7.9g/cm³). For screws of the same size, titanium is significantly lighter (for example, an M6×20 screw made of titanium is about 40% lighter than its stainless steel counterpart).

Magnetic testing: Titanium (pure titanium or common titanium alloys such as Gr2, Gr5) is completely non-magnetic. If a strong magnet (e.g., NdFeB magnet) is brought close to the screw and shows no magnetic attraction, it is not made of titanium. If there is no magnetic attraction at all, it can be preliminarily determined as a non-ferromagnetic material (possibly titanium, aluminum, etc.).

II. Simple and Practical Tests

Appearance and Luster: Pure titanium/titanium alloy screws have a base color of silver-gray/dark gray, with a "cold metallic luster" on the surface, which is brighter than iron/copper screws. If anodized/coated, they may appear in colors such as blue, purple, or gold (note that other metals may also be coated).

Scratch test: A screw is lightly scratched on a white ceramic surface (e.g. porcelain bowl). Titanium leaves a gray scratch, while stainless steel does not leave a noticeable scratch (however, some titanium screws have a hardened head, which may not leave a scratch).

The sound of tapping. When a screw is tapped, titanium will produce a crisp, high-frequency sound; stainless steel/iron will produce a more muffled sound.

III. Advanced Verification Methods

Chemical test: A small amount of dilute nitric acid on the surface of the screw, pure titanium will instantly produce small bubbles (titanium and nitric acid reaction); stainless steel / iron will not have obvious reaction (or slow reaction).

Material identification: The head of standard titanium screws typically bears material markings (e.g., TA2, TC4, Gr2, Gr5), which correspond to specific titanium alloy standards (e.g., TC4 corresponds to Ti-6Al-4V).

IV. Professional and precise methods

Laboratory testing: Precise determination of material composition and properties through spectral analysis, tensile testing, and other methods.

Titanium is a costly material, and titanium screws are typically several times more expensive than stainless steel screws of the same specifications. If the price is too low, it is highly unlikely to be titanium. It is recommended to choose reputable manufacturers (such as Baoji Chengjin Titanium Industry Co., Ltd.) and request a material quality inspection report.