ASTM E2371-Chemical Analysis of Titanium by Spark Atomic Emission

Standard Test Method for Analysis of Titanium and Titanium Alloys by Spark Atomic Emission Spectrometry

ASTM E2371 specifies a rapid, multi-elemental method for determining the chemical composition of titanium and titanium alloys using Spark Atomic Emission Spectrometry (Spark-AES), also known as optical emission spectrometry (OES).

It is especially useful for routine quality control in production environments.

1. Method Principle

A high-energy electrical spark is applied between an electrode and a solid, flat titanium sample.

The energy excites atoms in the sample surface, causing them to emit characteristic wavelengths of light.

These emissions are detected by a spectrometer and converted to concentration values using pre-calibrated reference materials.

2. Elements Typically Determined

Major Alloying or Interstitial Elements

Aluminum (Al)

Vanadium (V)

Iron (Fe)

Oxygen (O)

Nitrogen (N)

Carbon (C)

Hydrogen (H)-typically via separate method

Silicon (Si), Nickel (Ni), Molybdenum (Mo), etc.

The specific element set depends on the grade being analyzed (e.g., Gr 5: Al, V, Fe; Gr 2: O, N, Fe, C).

3. Typical Application Range

Spark-AES is effective for determining element levels in the range of ppm to a few percent, suitable for both CP titanium and alpha-beta alloys like Gr 5 and Gr 23.

4. Sample Preparation Requirements

Form: Flat solid sample (e.g., plate, bar, billet)

Surface prep: Machined, ground, or lathe-turned to ensure smooth, oxide-free surface

No coatings, oil, or contaminants

Surface condition is critical. Inaccurate or inconsistent prep leads to incorrect results.

5. Reporting Results

Reports using ASTM E2371 typically include:

Sample identification

Grade designation (e.g., ASTM B348 Gr 5)

Individual element concentrations (in wt.% or ppm)

Instrument calibration info

Method reference: ASTM E2371

6.Related Standards

ASTM E1409-Carbon content in titanium alloys

ASTM E1447-Hydrogen in titanium (inert gas fusion)

ASTM E1941-Oxygen and nitrogen by inert gas fusion

ASTM E2371-Full alloy analysis by Spark-AES (this one)

ASTM B348-Titanium bar standard (references E2371)

7.Common Use Cases

Certification of raw materials (billets, bars, slabs)

Incoming inspection at machining or forging shops

Generating mill test certificates (MTCs)

Verifying compliance with ASTM B348, B265, F136, etc.