Machine shops often need open die forged parts for a variety of applications, including large, custom parts, small quantity runs or when high strength and durability are required. When this is the case, machine shops often contract with forgers for “as forged” parts and then perform finish machining and other secondary operations to achieve the precise tolerances, dimensions and surface finishes required by the customer.
However, purchasing a near net shape forging may be a better option, one that allows machine shops to reduce costs and improve their profit margins.
Near net shape forgings are seamless rolled rings or open die forgings with dimensions close to the final shape of the finish machined part. “As forged” components, on the other hand, often have a coarse surface finish (500 RMS or more) and may include metal scales and very uneven surfaces that must be machined away. This increases the cutting time, tool wear and cutting fluid used, which eats into profits. When a customer is on a tight budget, extra stock material that becomes metal swarf can mean the difference between winning a job and losing one.
Fortunately, near net forgings are available with tolerances within 3mm on all dimensions and a much finer surface finish. Although the initial price may be higher, the reduced machining time, wear, elimination of waste and faster delivery time to the customer translate into cost savings and profit improvements. Reduced machining time increases machine availability for additional projects as well.
Near net forgings are more than just ODs, IDs and lengths. They include steps on round shafts, blocks, squares, rectangles, hubs, wheels, cylinders, blind cylinders, flanges, drive ends, tending ends and complex shapes. All Metals & Forge is an ISO 9001:2015 and AS9100D-certified manufacturer of open die forgings, seamless and contoured rolled rings and complex forged parts with stock allowances or near net shape tolerances.
Machining Open-Die Forgings
Open die forgings and seamless rolled rings play a crucial role as components in gears, turbines, bearings, clutches, brakes, couplings, drives, flanges, valves, machines and rollers. Industries that rely on these types of parts include aerospace, automotive, defense, energy, engine and turbine, food processing, mining, oil and gas, petroleum, power generation, pulp and paper and shipbuilding.
Given the critical role of these components, open die forgings provide a higher level of structural integrity than any other metalworking process by eliminating structural voids and improving the directional grain flow and grain size within the material.
Seamless rolled rings, like those made by All Metals & Forge Group, an ISO 9001:2015 and AS9100D-certified manufacturer of open die forgings, seamless and contoured rolled rings and complex forged parts, for example, resist wear, fatigue and stress, enabling better performance. Depending on the metal and alloy, the rings or forgings are also resistant to thermal and chemical damage, which further extends longevity while reducing the need for maintenance, repair and replacement.
Open-die forging is particularly advantageous when fabricating large, custom components. All Metals & Forge Group can produce seamless rolled rings or contoured rolled rings up to 200 inches in outside diameter and custom forgings up to 40 feet long or 80,000 lbs. Small parts down to roughly one foot cubed can be deliver as near net shape forgings as well.
Near net shape forgings may be slightly more expensive until all the machining cost factors and savings are calculated into the final part price.
When parts are machined from a basic profile, such as a block, round or rectangle, significant stock can be lost, but you are still required to pay for the excess material. With open die forging, the part is shaped by the dies, significantly reducing material waste.
These forgings come with tolerances within 3mm and smoother surface finishes, which means less material removal and faster delivery times.All Metals & Forge Group
When the job is for multiple parts, near net shape savings begin to add up. There are also unseen savings, such as the time to reorder cutting bits, restock cutting fluids, recycle metal swarf and the opportunity to increase machine time availability.
Greater savings can be achieved with the purchase of a near net shape forging with a fine surface finish when the final profile is more intricate. In the example of a 10-inch round bar 120 inches long with allowance to finish to final dimensions, one supplier may offer the forging with one-quarter inch allowance or 10.25 OD x 120.25 inches long. The forging will weigh approximately 2,814 pounds in most steels. A supplier that can deliver the part with only a 3mm allowance reduces the weight of the bar to 2,739 pounds – a difference of 75 pounds. The extra 75 pounds on this simple profile increases the purchase price, waste and machine time, which is invariably passed on to the customer.
Open die forgings can be made of carbon steel, alloy steel, stainless steel, tool steel, nickel, titanium and aluminum. The forgings meet rigorous industry specifications such as ASTM, AMS, AISI, ASME, SAE, DIN, ASME B 16.5, ASME B16.47 and API 6A. In addition, ultrasonic testing routinely performed by All Metals & Forge Group at no extra cost ensures the absence of internal cracks, pits or voids.
The limits of near net shape forgings are defined by the supplier. When even more precise tolerances and finer surface finishes are required, a company like All Metals & Forge can deliver parts to within +/-0.001 inch of drawing dimensions and 64 or 32 RMS surface finish.
Near net shape open die forgings and seamless rolled rings can be a strategic competitive advantage for machine shops of all sizes, whether a standalone business or one operating within an OEM facility.
By improving quotes by just a percentage point or two on each bid related to open die forgings or seamless rolled rings, machine shops have the potential to increase profits and internal cost savings.