T171

Overlay

T171

T171 is a patented iron based steel overlay wear solution with a near nanoscale (submicron) microstructure. T171 is well suited for the toughest jobs in the most extreme service envi- ronments. T171 is developed by Trimay® Wear Plate Ltd. using Nano technology.

T171 is a steel alloy with a unique glass forming chemistry that allows high undercooling to be achieved during weld- ing. This results in considerable refinement of the crystal- line microstructure to a near nanosize (submicron) range.

The ultra refined microstructure allows T171 to provide vastly improved hardness that lasts significantly longer than traditional carbide remedies.

High Hardness

T171 maintains maximum hardness performance of 68-71 HRc from the weld interface throughout the entire overlay in single pass applications.

This allows the overlay to be fully protective throughout the volume. The micrograph to the right shows how 68-71 HRc maximum hardness is achieved within several microns of the weld overlay interface.

HRc hardness values in the micrograph were measured from a single pass T171 overlay applied to 44W/300W mild steel plate substrate.

Exceptional Wear Resistance

T171 provides exceptional resistance to severe sliding abrasion in extreme service environ- ments.

T171 can be built up to 1/2” overlay thickness in two passes as necessary with all layers providing maximum wear resistance of 0.08 – 0.10 g (+/- 0.03) mass loss in ASTM G65-04 abrasion test.

Impact Resistance

The superior toughness of T171 results from the in-weld formation of a large quantity of refined complex borocarbide phases which are surrounded by ductile ferrite phases.

The borocarbide phases are completely wetted by the matrix and prevent premature pull-out, delamination and crack nucleation. Their refined nature allows the reduction of stress concentration sites and the ductile matrix supplies effective crack blunting and bridging, resulting in improved impact resistance.

Production and Installation

As a wear plate solution, T171 can be applied as an overlay on carbon steel and low alloy steel substrates. T171 wear plate is produced using Trimay’s® proprietary submerged arc process.

T171 wear plate responds very similar to standard chrome carbide overlay during forming, cutting and fabrication. T171 wear plate can be rolled or formed by press brake into desired shapes for specific applications. Formability is similar to standard overlays and dependant on thickness and weld position on the inner or outer diameter. Plasma arc or water jet cutting is recommended for shape cutting and large hole piercing.

Like other overlays, T171 wear cannot be flame cut. For applications requiring less precision, T171 overlay material can be removed by means of carbon arc gouging. T171 overlays are non-machinable and, if necessary, surface finishing can be done by grinding or EDM.

T171 wear plate can be installed by plug or fillet welding, or bolted into place. T171 over- lain pipelines can be threaded and coupled together or flanged much like regular steel pipelines. Any weld seams should be overlaid with T171 wire, available exclusively to Trimay® customers, to protect from wear caused by undercutting of the overlay at the seams.

Single Layer HRc Hardness.

HRc hardness properties are consistent throughout the entire layer.

SEM Micrograph – 500x

T171 microstructure showing uniform distribution of borocarbide phases.

Application Process

Sub Arc Bulk Welding

Wear Resistance

ASTM G65-04 Procedure A 6,000 cycles mass loss
0.08g (+/- 0.02)

Deposit Properties

Density (g/cm³) 7.36

Rockwell C (HRc) Hardness

HRc 68- 71

Impact Resistance

Drop Impact Testing – Passed

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