Gauge Blocks

DuraGrade steel is the most appropriate gauge block material wherever steel components and instruments predominate. Industry trials by Alan Browne Gauges have demonstrated that in use DuraGrade steel gauge blocks are 5 times more wear-resistant than gauge blocks made from plain carbon nd low-alloy tool steel.

05Material – Composition

DuraGrade steel gauge blocks are manufactured from AISI A7 tool steel. The metallurgical composition of this steel is:

C                      V                      Cr                   W                  Mo                 Mn                    SI

2.30                4.75                5.25                1.1                1.1                 0.50                    0.50%

Wear-resistance

The American Society for Metals states:- “The outstanding characteristic of this steel is extremely high wear resistance” This wear-resistance is the result of a uniform dispersion of fine vanadium carbide, the hardest known carbide, throughout the steel. Industry trials by Alan Browne Gauges have demonstrated that in use DuraGrade steel gauge blocks are 5 times more wear-resistant than gauge blocks made from plain carbon and low-alloy tool steel.

Dimensional stability

The dimensional stability of DuraGrade steel gauge blocks to ISO 3650 requirements was initially verified at NPL and has continued at Alan Browne Gauges over a 20 year period.

Other physical properties

The coefficient of thermal expansivity of this steel has been established at Alan Browne Gauges and NPL to be 10.65 x 10-6 /_C. The thermal conductivity and elasticity of this steel are also similar to hardened tool steel, enabling ‘like with like’ measurement.

Conclusion

DuraGrade steel is the most appropriate gauge block material wherever steel components and instruments predominate.

Specifications – Standards

DuraGrade steel gauge blocks comply with international standard ISO 3650 and the equivalent national standards

Grades

DuraGrade steel gauge blocks are supplied in all ISO 3650 grades to fulfil a wide range of application requirements:-

Grade K:

• for use as reference standards for the calibration of gauge blocks in grades 0, 1 & 2.

• Reference standards in wear resistant DuraGrade steel.

• Calibrated by Interferometry to UKAS Class A

Grade 0:

• for calibrating high quality metrology equipment in a calibration environment.  01

• Calibrated by comparison to UKAS Class B.

• Supplied in sets and as single blocks

Grade 1:

• for checking Inspection items within an inspection area.

Grade 2:

• For general workshop use.

• Calibrated by comparison to UKAS Class C.

• Supplied in sets and single blocks.

Grade 00:

• for applications demanding the highest degree of precision.

• Calibrated by Interferometry to UKAS Class A

Warranty

All new sets of DuraGrade steel gauge blocks in Grades 0, 1 and 2 carry the two year DuraGrade warranty

“We will replace free of charge any gauge block in a DuraGrade set if recalibration in our laboratory, within 2 years of the date of supply, shows that the central length deviation of the gauge no longer complies with the original grade of the set.”