Heat Treatment Of Crusher Wear Castings And Why 30 Seconds Matters

What Solution Treatment Does

Austenitic manganese steel only works if the carbides are dissolved into solution and held there. That means heating the casting to temperature, holding it long enough for the section to equalise, and then cooling it fast enough that the carbides have no opportunity to re-precipitate at the grain boundaries.

A casting that cools slowly has carbides in the grain boundaries, and those boundaries are then brittle. The part will crack in service rather than work harden.

Uniform Heating

Castings are spaced in the furnace rather than stacked. The spacing exists so that every surface heats uniformly and, more importantly, so that every surface meets water freely at the quench.

A casting packed tightly against its neighbour has a face that heats late and quenches slowly. That face carries the defect through the whole service life.

The Thirty Second Rule

Quenching begins within 30 seconds of the casting being withdrawn from the oven. This is not a nominal figure — every second between furnace and water is a second of slow cooling at exactly the temperature range where carbides precipitate.

It is the single most demanding logistical requirement in a wear-parts foundry, and it dictates how the furnaces, the crane and the pool are laid out.

The Quench Pool

Our pool holds 2,000 m³ and has an underwater circulating and stirring system. The volume matters because a large casting entering a small pool raises the water temperature and slows its own quench.

The circulation matters because a static pool forms a vapour blanket against the casting surface, which insulates precisely where cooling needs to be fastest.

Heat Treatment Capacity

• Trolley heat treatment furnace 3 m × 3.5 m × 2 m, one set.
• Trolley heat treatment furnace 3 m × 2.5 m × 1.8 m, two sets.
• 2,000 m³ heat treatment pool with circulating and stirring system underwater.
• This is the capacity that makes single castings up to 10 tonnes possible — pouring a part that size is only half the problem.