How We Do It :: Extrusion Department

Overview

In this process, cast blocks are heated to very high temperatures, and then hot worked directly into much smaller products by high pressure hydraulic presses. Cutting, cleaning and marking operations result in semifinished products ready for further processing.

Prepping the Billets

The Extrusion Department in Ansonia receives billets and blocks from Casting as well as outside suppliers for special high copper alloys. Billets are cut to length and loaded into the Elhaus block heater furnace which raises the temperature up to the hot working temperature (700 to 1000 C ) in about ____ hours.

The Schloemann, 4000 ton indirect extrusion press loads the hot block in a container with the back end closed with a closure plate. The hydraulic, hollow stem, with the extrusion die on its end, is pressed into the front of the block, forcing the extrusion to exit through the stem to the coilers or table.

Extrusion Part 1: "Shell Extrusion"

Ansonia's process is "shell" extrusion which removes the outside surface of the cast block during the push for surface quality improvement.

Complex Combinations

The practices developed by the extrusion crews, metallurgists and supervisors are carefully documented and contain many complex combinations of temperatures, speeds, die materials, lubrication practices, and cooling methods, each intended to produce sound, good surface extrusions of exactly the right size and structure.

Finishing Touches

Acid pickling to remove oxides from the high heat, along with inspections and tests to assure metallurgical quality, are the finishing touches before the extrusions are delivered to the Rod or Flat Wire Departments.

Tube Extrusions

Tube extrusions are made on our Watson-Stillman 3000 ton direct extrusion press which can process solid or bored blocks either by shell or lubricated extrusion.

Extrusion Part 2: "Direct" Extrusions

With "direct" extrusion, the heated block is placed in the container, the die in the front and a donut shaped dummy block in the back. The hollow press ram squeezes the block tight to the die and the mandrel pierces the block, followed by extrusion of a tube shell.

Heating is by Induction heaters that raise the block temperature to 900 C in 10-12 minutes. As-extruded tubes are trimmed and pickled clean before further processing.

Complex Combinations

Again, the carefully developed and documented extrusion practices, depend on complex combinations of temperatures, speeds, dies, lubricants, and cooling methods, to produce good extrusions.

Hot working by extrusion is a complex but efficient method of getting our casting starting stock as close as possible to finish size. With associated heating and finishing costs, we now have about 40-50 cents per pound of value added to products as-extruded.

Tube as a Supplier

Tube Extrusion is a supplier to the rest of the Tube Mill and it also extrudes large diameter rod for the Rod Department.

Continue to rod department here.

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