Standards Development

Scope

This document specifies the determination of total aluminium and total boron in steel and alloy by microwave digestion-inductively coupled plasma mass spectrometry.

This method applies to determining total aluminium mass fraction between 0,000 5 % and 0,10 %, and total boron mass fraction between 0,000 2 % and 0,10 %. 

Purpose

The total aluminium and total boron content in steel have an important influence on the performance of steel. For example, an appropriate amount of aluminium can refine the grain and improve the strength and toughness of the steel; while boron can play a key role in improving the hardenability in some special steel grades. Currently, there are differences in the determination methods and standards for the total aluminium and total boron content in steel among different countries and regions, which brings many inconveniences to international trade and even forms trade barriers.

The aluminium content of ultra-pure steel and spring steel is controlled below 0.005 %, and adding trace boron can improve steel properties. Trace aluminium and boron in steel and alloys greatly influence steel properties, so it is very important to analyse them.

However, the standards that exist in ISO TC17/SC1 are limited. The target of determination and the scope can’t meet the needs of the products. 

The existing determination of trace aluminium is concentrated in the Flame atomic absorption spectrometric method (ISO 9658: 2024), the determination of aluminium with mass fraction is 0,005 % ~0,20 %, and it is impossible to determine aluminium with mass fraction below 0,001 %. Trace aluminium is concentrated in glow discharge optical emission spectrometry (ISO 19272:2015), but the target of determination is low alloyed steel and the aluminium mass fraction is 0,006 %~0,90 %. The existing methods for the determination of trace boron are mostly the Curcumin spectrophotometric method (ISO 101531997 and ISO 139001997), which has poor selectivity and is often separated by methanol distillation, which is harmful to the human body.

On one hand, there is currently no appropriate standard method, so it cannot meet the needs of actual production. It is urgent to establish the ISO standard method for steel and alloys. On the other hand, with the increasing demand for the determination of trace aluminium and boron, and the popularization of domestic microwave digestion technology and ICP-MS technology, the conditions for establishing an analytical standard for the determination of total aluminium and total boron in steel by microwave digestion ICP-MS have been met.

The use of microwave digestion for sample dissolution has the advantages of low blank of boron and aluminium, less salt matrix, and fast speed. ICP-MS has high sensitivity and a wide linear range, which can meet the analysis requirements of the content range of 0.000 1 % to 0.1 %. The combination of microwave digestion and ICP-MS can well solve the determination of trace total aluminium and total boron in steel. This method specifies the determination of total aluminium and total boron in steel and alloy by microwave digestion-inductively coupled plasma mass spectrometry. It is suitable for the determination of total aluminium and total boron content in steel and iron.

In conclusion, the establishment of the ISO standard for the determination of total aluminium and total boron in steel has great practical significance and far-reaching historical significance. It will have a positive impact on quality control, international trade, environmental protection, and scientific research in the steel industry, and promote the sustainable development of the global steel industry.