Specs called for fabricating two cones of AR 500 with a 32.125-inch circumference tapering to a 15.5-inch circumference within the 8.375-inch-high workpiece. The two braces replaced more expensive fixturing.

After forming, the welder used hydraulic clamps to hold the joint gap of 0.125 inch, and to shape the ends of the cone to the required circumference. A brace across each end held the dimensions during welding.

When the bid request arrived to fabricate two cones made from 0.375-inch AR 500 steel, Bob Henderson, joint owner of Farasey Steel Inc., Cleveland, Ohio, expected difficulty in holding to the required dimensions. AR 500 is designed to reach a nominal hardness of 500 BHN (Brinell hardness) for resistance to impact and sliding abrasion. It is often selected as a liner for mining and material handling equipment — off-road dump bodies, chutes, bins, silos, gates, buckets and hoppers.

The job specs called for a 32.125-inch circumference tapering to 15.5 inches within an 8.375-inch-high cone. Henderson had the piece cut on a plasma-arc table, then formed on a 600-ton press break. The 500 BHN of the metal (as an indicator of plastic flow, mild steel would have 62 BHN) and the required cone shape would not allow rolling the pieces.

Two-Piece Order
If the order had called for more pieces, Henderson would have designed and built a fixture to hold the cone for welding. But that was costly for only two pieces.

So, after forming, the welder used power clamps to hold the joint gap of 0.125 inch, then he held the gap with tack welds.

"I measured the inside circumference and divided by 3.14 () to determine the true diameter for each end of the cone," says Henderson. "We could not accept a straight line measurement because it could have an oblong shape. Once we knew the measurements, we could use the hydraulic clamps to carefully shape the cone to the circumference that we needed."

With the cone in proper shape, the welder tacked a brace across the small end. He then welded a plate on each end of the joint to start and finish a weld of the joint from the inside.

After another measurement and necessary adjustments with the power clamps, the welder tacked a second brace across the wide end. He carbon-arc gouged and ground the joint to 0.125 inch. He then made a full penetration weld of the joint from the outside. After a final measurement and clamp squeezes, the welder took off the braces and end plates. The finished cone included a large dose of ingenuity, fit-up and welding skills to keep the price competitive.

The customer liked the price and the workmanship well enough to request bids on two other jobs that are now in the shop.