Jaw Crusher
Spare & Wear Parts

By impact energy, not by the highest number. Manganese castings start at roughly 200 HB and work-harden in service to 450-550 HB — but only where the application delivers enough impact to trigger it. Mn14 suits lower-impact duty and smaller machines; Mn18 is the workhorse for granite, basalt and general hard rock; Mn22 is for sustained high-impact primary crushing in large jaws. The counterintuitive part: a harder grade in the wrong duty wears faster, because it never work-hardens and abrades away as raw austenite. Tell us your feed and closed-side setting and we specify the grade.

When changeout downtime costs more than the plate. Inserted parts run roughly 40-60% higher upfront and typically return 2-3 times the service life of standard manganese in abrasive duty, with replacement frequency down by more than 60%. That arithmetic works in high-silica, high-tonnage operations. It rarely works in soft limestone, where a standard Mn14 plate already lasts a long time and the premium never pays back.

Expect the 2-3 times range, and understand why the baseline is short. Granite has a Bond abrasion index around 0.55 against limestone's 0.001-0.03, and basalt carries a Bond work index near 20 kWh/t. In that duty standard manganese typically runs 100-300 hours between changes. The same part in limestone can last 5-15 times longer — which is why the premium case is strong on granite and basalt and weak on soft rock.

Cracking is usually a specification problem rather than a casting defect: our manganese liners are tested cast by cast before they ship, so a manufacturing fault is the uncommon explanation. The most common cause is a grade too hard for the impact available — high-manganese grades need sustained impact to work-harden, and without it the austenite stays soft in bulk while the surface fatigues. The other frequent cause is seating: a plate that does not sit flat against the backing takes bending loads it was never designed for. Send us the failure photographs and the machine model and we will tell you which of the two it was.

Three levers, before you change anything you buy. Choke feed the chamber: running low or intermittent feed lets rock hammer the plates without a cushion. Reverse the plates — most designs can be turned 180 degrees once one end wears, close to doubling usable life. Match the tooth profile to the job: deep, widely spaced teeth for coarse primary feed; shallower, closer teeth for secondary duty and finer product. Plants that manage feed and settings deliberately report 30-50% more plate life than those that do not.