ASTM F140

ASTM F140 is the standard practice for making reference glass-metal butt seals and testing their expansion characteristics by polarimetric methods. It is used to support consistent evaluation of glass-to-metal sealing behavior, helping users compare seal performance under controlled conditions. By defining a repeatable practice for preparing reference seals and assessing expansion-related characteristics, the standard supports more reliable technical review, quality control, and product consistency in applications where matched thermal behavior is important.

Purpose of ASTM F140

The purpose of ASTM F140 is to provide a recognized practice for producing reference glass-metal butt seals and examining expansion characteristics with polarimetric methods. This helps establish a common basis for testing and comparison when evaluating how glass and metal interact in a sealed assembly. As a technical document, it is generally used to improve consistency in measurement and to support informed decisions during development, acceptance, or qualification work involving glass-metal sealing systems.

Common use cases of ASTM F140

ASTM F140 is commonly used in laboratory and quality-control settings where glass-metal butt seals must be prepared and assessed in a repeatable way. It is relevant to workflows that involve seal development, reference sample creation, and expansion-related testing by polarimetric methods. The standard may also support procurement or evaluation activities when a clear technical basis is needed for comparing sealed assemblies and confirming that test results are obtained under a consistent practice.

Why ASTM F140 matters

ASTM F140 matters because it helps reduce variation in how reference seals are made and how expansion characteristics are assessed. That consistency is valuable for compliance efforts, product evaluation, and technical comparison across different samples or suppliers. When glass-metal sealing performance must be reviewed carefully, a defined standard practice can improve confidence in test results, support risk reduction, and make it easier to document and communicate acceptance criteria in engineering and quality programs.

• Reference glass-metal butt seal preparation
• Polarimetric expansion testing practice
• Repeatable comparison of seal behavior
• Quality control and technical evaluation support