Tool Steel-Lined Barrels

June 15, 2022

Premature and uneven cylinder wear is expensive in terms of both replacement costs and lost process efficiency. IMS barrels are lined with your needs in mind. For low abrasion applications, we keep your costs down by using D-2 tool steel.

Barrel Liner Material Guidelines

D-2 Tool Steel
Heat treated to RC 58-60, D-2 is a relatively inexpensive, high carbon-high chromium steel with proven, uniform wear resistance surpassing most other steels.

Nitrided Barrels
Lined with Nitralloy 135M. Gas nitriding is available on barrels. Not recommended for use with abrasive or corrosive resins due to their inability to resist wear over an extended period of time.

CPM Family

CPM tool steels are premier products of Crucible Specialty Metals Division. The process of producing CPM tools involves gas atomization of pre-alloyed molten steel to form powder that is then isostatically compressed into 100% dense compacts. CPM steels have no alloy segregation and exhibit extremely uniform carbide distribution. The CPM process produces very homogeneous, high quality steel characterized by superior dimensional stability, grindability, and toughness compared to steels produced by conventional processes.

CPM9V
With a lower carbon and vanadium to improve toughness and heat check resistance, CPM9V performs well in problem applications where high carbon, high chromium tool steels, such as CPM10V or the high speed steels, lack sufficient toughness or heat check resistance, or where lower alloy tool steels and hot work tool steels lack sufficient wear resistance.

CPM10V
CPM10V has its vanadium content optimized to provide superior wear resistance while maintaining toughness and fabrication characteristics comparable to D2 and M2. Its exceptional wear resistance and good toughness make it an excellent candidate to replace carbide and other highly wear resistant materials in cold work tooling applications, particularly where tool oughness is a problem or where cost effectiveness can be demonstrated. Due to it’s 10% vanadium content, this steel is one of the most abrasion resistant materials available.

CPM15V
Intended for applications requiring exceptional wear resistance. It has more vanadium carbides in its composite than CPM10V and provides more wear resistance and longer tool life. CPM15V also offers an alternative to solid carbide where carbide fails by fracture or where intricate tool design makes carbide difficult or risky to fabricate. Due to it’s 15% vanadium content CPM15V will outwear CPM10V.

CPMS90V
A stainless steel with a high volume of vanadium carbides for exceptionally good wear resistance. Due to its high vanadium content for wear resistance and it’s sufficient chromium content, to provide good corrosion resistance, the wear and corrosion resistance of S90V make it an excellent candidate where increased wear is a primary concern. It can be heat treated to a lower hardness for use as a screw material or to a higher hardness (RC 58-60) for barrel lining.

Nitrided Barrels

Nitrided barrels may be made from 4140 but a nitriding steel, such as Nitralloy 135M enables a better nitrided interior surface to be achieved. Two nitriding methods are available: gas nitriding and ion nitriding.

Gas Nitriding
Gas Nitriding is used to create a surface hardness on the screw. The hard layer of steel will vary in depth from .007” to .015” depending upon the length of the nitriding cycle. The hard layer (usually well above 60 Rc) is achieved by heating the steel in an atmosphere of nitrogen (ammonia gas) at temperatures of 950˚F to 1050˚F. The nitrogen atoms are diffused into the surface of the steel, combining with nitride-forming elements, such as chromium, aluminum, molybdenum, vanadium, tungsten and titanium, to produce a very hard surface, particularly for the first .002” to .005” depth. Nitrided screws have a very good wear resistance until the surface hardness is worn away. After the surface is worn .007”, wear accelerates and the screw may quickly be worn to a condition that is beyond repair.

Ion Nitriding
Ion nitriding is similar to gas nitriding, using an electrical potential to ionize low pressure nitrogen gas. The ions produced are accelerated to the surface of the steel, heating it to a temperature for diffusion to take place (i.e., the uniting of the atomic nitrogen with the nitride-bearing elements in the steel). Because the temperatures are lower and pressures more controllable, a more uniform surface hardness depth may be achieved. The ionization occurs in a plasma discharge process which creates a glow, hence, this type of nitriding is also referred to as the ‘plasma method’ or ‘glow discharge’ nitriding.

Nitrided barrels are not recommended for use with abrasive or corrosive resins because of their inability to resist wear over an extended time period.

Bimetallic Barrels

Cast bimetallic barrels are manufactured by metallurgically bonding the lining alloy to the inner surface of a pre-machined, seamless steel tube, forging or bar stock. The bonding is achieved by heating the barrel (and the lining alloy) to the point where the alloy is melted. The barrel is then spun and cooled, centrifugally casting the alloy on the inner surface of the barrel. The casting is typically .040” – .080” in depth.

The linings range from standard abrasion-resistant, to corrosion-resistant, to premium. Each provides different degrees of wear resistance.

IMS manufactures bimetallic barrels in-house using top of the line cast bimetallic barrel blanks. We carry in inventory most common sizes of these barrel blanks in order to meet our customer’s needs.

Standard Bimetallic
Standard wear-resistant liner. Nickel-Boron alloy with good abrasion resistance and low friction co-efficient.

Carbide Bimetallic
Super wear-resistant tungsten carbide liner. For highly abrasive applications. Some corrosion resistance.

Premium Bimetallic
Corrosion resistant liner. Cobalt-nickel based with high chromium content. Provides excellent wear resistance in highly corrosive conditions.

Relined Barrels

IMS offers full-length relining of barrels up to eight (8) inches in diameter and 180” inches in length, using premium tool steels and special alloys, depending upon the customer’s need.

Upon receipt of your barrel, our engineers will do a thorough inspection of your barrel. We will then contact you with a quote for repair, either by phone or fax. At that time you will have the option of proceeding with the work (upon IMS’s receipt of your purchase order approval), having IMS return the barrel to you or having us dispose of it.

AN IMS ALTERNATIVE: R215 Carbide bound liner: We start with a solid piece of 4100 series tool steel with a bored ID. CO56 powder is then placed in the 4100 series barrel, heated up and spun. This makes the CO56 melt and stick to the inside of the barrel, similar to a sleeve. It is then bored to manufacturer specs and polished. This barrel can be later bored out and resleeved w/carbide or tool steel if necessary.

Bonding is achieved by heating the barrel (and the lining alloy) to the point where the alloy is melted. The barrel is then spun and cooled, centrifugally casting the alloy on the inner surface of the barrel. The resulting lining is about 1/16” (.0625”) thick throughout the barrel. Due to the temperatures reached in the spin-casting process, the 4100 series backing material is annealed. In larger barrels, a pressure sleeve made from heat treated or forged alloy steel is placed over the nozzle end
of the barrel by shrink fitting.

(1) All Thermoplastics without reinforcement or abrasive fillers.
(2) Thermoplastics with abrasive reinforcement or fillers up to 30%.
(3) Thermoplastics with 30% or more reinforcements or abrasive fillers and thermosets.
(4) Cellulosics, lonomers, Acetals and others containing corrosive additives.
(5) Fluoropolymers.

Measuring Barrel Wear

• Clean the barrel ID, while hot, with a soft wire or brass brush, preferably wrapped with copper gauze. Allow to cool to room temperature.
• Set dial bore gage to nominal bore diameter of the barrel. Record your findings, taking a reading along the ID of the barrel every 2 – 3 inches. Examine condition of barrel ID, looking for any “washed out” areas, cracks and gouges. Inspect feed throat area and end cap.