Pit & Quarry, January 2014

PARTS SELECTION Wear steel N BY RICH FERCY early every piece of equipment features wear resistant steel As a consumable item the steel wears out No one has the time to test 17 different wear plates head to head Nor do they have the time to track which wear plates went where and how long they lasted Unfortunately there is no industry standard for abrasion resistant AR steel Most people believe all AR400 is the same But they definitely are not the same and here is why Few people understand AR steel because of inaccurate information The truth is that any number of steels can be compared in minutes using data found online or in the manufacturers printed material With the information users will never have to install underperforming wear plates again A quick education Lets be honest You dont think about the wear resistant steel in your equipment until it completely wears out But you must take immediate action when it does So you either order the same steel as last time or throw in whatever is laying around As a last resort youll look for something cheaper than last time Think about pizza for a moment Looking at a pizza you can see every ingredient Whether piping hot ready to bake or frozen one glance tells if you will like the taste Why is this important Different pizzas have different topping quantities Just like pizza the same elements are used to make steel wear plate Creating a longer lasting wear plate that also handles impact really depends on three critical steps Getting rid of sulfur and phosphorus Minimizing oxygen in the molten steel Having the proper balance of alloying elements to make the steel hard all the way through Sulfur and phosphorus make steel brittle Blasting 1200 cu ft per minute of oxygen into molten steel removes the phosphorus As an example a total of 103 ships were lost in World War I Many sank from a relatively minor bump with another ship In another case Titantics the ship sank after striking an iceberg After considerable research it was discovered that the steel used to make the ships had high sulfur and phosphorus levels This makes steel brittle If you have ever had a wear plate break high sulfur levels are very likely the reason The top plate has a representation of 0002 percent sulfur For comparisons sake the 0002 percent equals one tablespoon of chopped onions Too much sulfur in a wear plate is like a pizza with too many onions It quickly becomes undesirable One critical detail to remember is that a sulfur level of 0002 percent has 30 ft lbs of impact resistance while sulfur at 0004 percent has 10 15 ft lbs of resistance That 0002 percent more sulfur creates the risk of more cracking problems in every wear plate application So examine sulfur content closely Both manganese and silicon help remove oxygen They also add strength and are very inexpensive so everyone uses them But loading up on manganese and silicon only creates brittle steel Manufacturers use silicon to add strength cheaply But adding more than 03 percent silicon Not all wear resistant steel is the same so find out exactly what youre buying before placing your next purchase order Hadfield manganese steel contains 12 to 14 percent or more manganese At that level the manganese can work harden from repeated impact 62 PIT QUARRY January 2014 www pitandquarry com