How Does Hardening and Tempering Improve the Strength of Materials?

Material strength isn’t a straightforward property, not when we’re talking about structurally-capable alloys. Yes, a hardened work piece is stiff, but it could also be brittle. In reality, strength is an amalgamated property, something that combines hardness and material tempering. In using metal solidification technology as our starting point, we’ll explain the importance of hardening, then we’ll introduce tempering, a process that counters the hardening work by adding ductility to the alloy amalgamation regime of Induction Hardening in Faridabad.

Determining Central Precepts

The purpose of the hardening stage is to ensure it won’t deform, no matter how heavy the applied load. If that load compresses the metal part won’t collapse in upon it, won’t fracture, nor warp. Instead, it stands resolute, with its original shape locked in place. In essence, the mechanical backbone of the processed metal is stiffened. But wait, a structure that’s imbued with this lone property could crack and crumble, unless there’s a ductility feature in place, that is. Workpiece tempering assumes this role, for this important low-temperature work phase is purpose-built as a material brittleness alleviator.

Heat Treatment Balancing and Counterbalancing

If a super-heated environment raises the transformative temperature of a selected alloy past its specified critical transformation threshold then is cooled rapidly, the workpiece hardens. Technically speaking, all pearlite content has been converted into martensite, an allotrope whose needle-like microcrystalline structure is extremely hard. The problem here is the brittleness of the martensite, an issue that can introduce stress and material deformation, although these effects are mitigated somewhat by the length of time the part was held at its transformative temperature. Tempering is required to counteract the strengthening (hardening) phase, a stage that can add material weakness (brittleness). The work piece has been hardened and rapidly cooled, via a quenching station, so now the tempering process enters the heat treatment line as a counterbalance. Again, heat is the brittleness mitigating agent, but this is a reduced thermal load, a heat source that increases material strength by adhering to a low temperature. Intelligently managed in this manner, the tempering temperature reduces alloy brittleness while augmenting the work piece’s strength and overall ductility of Case Hardening in Faridabad.

We’ve described quite a few hardening and tempering methods over the months. They create tough metal parts and superior finishes, parts that are as material strong as they are corrosion-resistant. Still, what we’re stressing today is an overall strategy, a meeting of different heat treatment principles and processes. Designed to produce a desired hardness-to-strength ration, the hardening and tempering equipment use time and fiery temperatures to imbue a chosen part with a requisite material strength rating in Induction Hardening.

Difference between - Induction Hardening & Induction Flame Hardening

Induction Hardening

Induction hardening is a process used for the surface hardening of steel and other alloy components. The parts to be heat treated is placed inside water cooled copper coil and then heated above their transformation temperature by applying an alternating current to the coil. The alternating current in the coil induces an alternating magnetic field within the work piece, which if made from steel, caused the outer surface of the part to heat to a temperature above the transformation range. Parts are held at that temperature until the appropriate depth of hardening has been achieved, and then quenched in oil, or another media, depending upon the steel type and hardness desired. 

The core of the component remains unaffected by the treatment and its physical properties are those of the bar from which it was machined or preheat treated. The hardness of the case can be HRC 37 - 58. Carbon and alloy steels with carbon content in the range 0.40 - 0.45% are most suitable for this process. In some cases, parts made from alloy steels such as 4320, 8620 or 9310, like steel and paper mill rolls, are first carburized to a required case depth and slow cooled, and then induction hardened. This is to realize the benefit of relatively high core mechanical properties, and surface hardness greater than HRC 60, which provides excellent protection.

While Induction Hardening is most commonly used for steel parts, other alloys such as copper alloys, which is solution treated and tempered, may be induction hardened as well. Applications include hardening bearing races, gears, pinion shafts, crane (and other) wheels and treads, and threaded pipe used for oil patch drilling.

Induction Flame Hardening

Flame hardening is similar to induction hardening, in that it is a surface hardening process. Heat is applied to the part being hardened, using an oxy- acetylene (or similar gas) flame on the surface of the steel being hardened and heating the surface above the upper critical temperature before quenching the steel in a spray of water. The result is a hard surface layer ranging from 0.050" to 0.250" deep. As with induction hardening, the steel component must have sufficient carbon (greater than 0.35%). The composition of the steel is not changed; therefore core mechanical properties are unaffected. Flame hardening produces results similar to conventional hardening processes but with less hardness penetration. Applications for flame hardening are similar to those for Induction Hardening in Faridabad, although an advantage of flame hardening is the ability to harden flat surfaces. Flat wear plates and knives can be selectively hardened using this process.

BASIC FUNCTIONS OF A LUBRICANT

In order to lubricate successfully, a basic understanding of a lubricant’s function is necessary. A lubricant, whether it is oil or grease, can at any time perform up to six basic functions simultaneously.

These functions are to:

• Reduce friction

• Reduce wear

• Absorb shock

• Reduce temperature*

• Minimize corrosion

*REDUCE TEMPERATURE

A major benefit of reduced friction is reduction in operating temperature. Caution must be observed in the overall assessment here. Because excessive lubricant may cause fluid friction, which may in turn raise the temperature of Induction Hardening in Faridabad.

Assuming that the correct quantities of lubricant are used, lubricants can be an excellent dissipater of heat, especially in re-circulative oil (or splash oil) systems where the Oil Coolers in Faridabad is passed over the moving part – where it not only lubricates, but also absorbs the heat and returns to the reservoir where it cools before recommencing the cycle. (Sometimes it is necessary to pump the lubricant through oil cooler, which will allow for a smaller reservoir.)

Induction hardening machine for brake shoe

Brake shoe refers to the action of the brake cam or the push rod is pushed toward the outside press brake muster brake function parts, the shape of the half moon. Brake position to the half moon high frequency quenching, increase wear resistance and service life of quenching process quality can inquire now @ inductwell.com

Features Of Induction hardening machine for brake shoe

Brake shoe refers to the action of the brake cam or the push rod is pushed toward the outside press brake muster brake function parts, the shape of the half moon. Brake position to the half moon high frequency quenching, increase wear resistance and service life of quenching process quality can make the braking effect better, our advanced technology and operation control can simultaneously quenching four crescent slots, high efficiency, saving labor costs of Induction Hardening in Faridabad!

What is the technological difference between Case Hardening and Induction Hardening?

Two methods have become established for Induction hardening work pieces in mass production: case hardening and induction hardening. A comparison of these two methods shows their differences and the advantages of each.

Case Hardening vs. Induction Hardening – a Comparison

If one compares the two methods for hardening steel work pieces (for a general explanation of hardening see here: Hardening), then the first striking difference is the parts handling. While case hardening processes a large number of work pieces at the same time, induction hardening focuses on the individual work piece. With induction hardening, components are hardened work piece by work piece. For case hardening, “batch by batch” would be a better description.

Of courses, this has an impact on the manufacturing. While case hardening relies on parts logistics to carry parts between the production line and hardening, induction hardening can be integrated directly in the production line with a suitable hardening machine (e.g. MIND series) and be part of the cycle.

Case hardening in detail

As mentioned above, case hardening is done in batches. As with induction hardening, the goal is to harden the outer layer of work pieces. 

In case hardening the work pieces are hardened by carburization. The steel is heated to over 880 °C to become austenitic. Then coal is transferred into the part from a CO-emitting medium through the part’s surface. The diffusion causes the edge of the work piece to receive more carbon, while the carbon density remains the same toward the center. 

Hardening occurs after the application of carbon. Penetration of carbon is critical for the hardness and the depth hardness characteristic of the work piece. The hardening, i.e. the hardness and the hardening depth, is defined by the carbonization depth, the receptiveness and thus the harden ability of the steel, and the quenching. The more carbon is inside an area of the work piece, the more successful the hardening in that area. 

After hardening, the work pieces are annealed (for more information about annealing please see here: Annealing) to restore some of their plasticity. The goal of any hardening process is to make the edge resistant to mechanical loads while giving the part enough elasticity to deflect external forces without damage. 

There are two ways to influence the hardening depth in case hardening: One is to manipulate the heating of the work piece, e.g. by application of special pastes that prevent heating in certain places. The other is by influencing the quenching process, e.g. by immersing only certain parts of the work piece.  

With both methods, results are not particularly accurate and reproducible only within a relatively wide tolerance range. This is very different for Air Coolers and Oil Coolers in Faridabad.

Induction hardening in detail

As mentioned above, each part is hardened separately with the induction hardening technology. Each part is heat treated, quenched, and annealed (if necessary) separately.

In addition to integration in the production line, the great advantages of induction hardening are precise control and reproducibility of hardening results. 

To achieve this, the entire hardening process from the inductor and the applied energy and frequency to quenching and annealing is specially adapted to the relevant work piece. This yields excellent hardening results, even for work pieces with complex geometriesen

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Which hardening method is the right one?

Which Induction hardening in Faridabad process is suitable for an application depends on several factors. Both methods, case hardening and induction hardening, have advantages and downsides.

For the mass production of components in medium or large quantities however, induction hardening offers a range of benefits:

• With a suitable hardening machine, induction hardening can be fully integrated in the cycle of the production line and automated.
• Especially with induction hardening, results are reproducible, which contributes to a consistently high quality in production.
• This reduces unit costs considerably

Air & Fuel Oil Coolers - Turbine Lubrication System Components

Air Oil Coolers

Two basic types of oil coolers in general use are the air-cooled and the fuel-cooled. Air oil coolers are used in the lubricating systems of some turbine engines to reduce the temperature of the oil to a degree suitable for recirculation through the system. The air-cooled oil cooler is normally installed at the forward end of the engine. It is similar in construction and operation to the air-cooled cooler used on reciprocating engines. An air oil cooler is usually included in a dry-sump oil system. This cooler may be air-cooled or fuel-cooled and many engines use both. Dry- sump lubrication systems require coolers for several reasons. First, air cooling of bearings by using compressor bleed-air is not sufficient to cool the turbine bearing cavities because of the heat present in area of the turbine bearings. Second, the large turbofan engines normally require a greater number of bearings, which means that more heat is transferred to the oil. Consequently, the oil coolers are the only means of dissipating the oil heat and Induction Hardening Faridabad.

Fuel Oil Coolers

Induction Hardening Faridabad and the fuel-cooled oil cooler acts as a fuel oil heat exchanger in that the fuel cools the hot oil and the oil heats the fuel for combustion. Fuel flowing to the engine must pass through the heat exchanger; however, there is a thermostatic valve that controls the oil flow, and the oil may bypass the cooler if no cooling is needed. The fuel/oil heat exchanger consists of a series of joined tubes with an inlet and outlet port. The oil enters the inlet port, moves around the fuel tubes, and goes out the oil outlet port.

Induction hardening offers excellent hardness distribution with minimal defects

Induction hardening offers significant advantages over traditional methods for heat-treating steel, alloy, and other metal parts. This process is perfect for metal with a carbon content of more than 0.3%, particularly hardened steel with a low alloy content (C34, C35, C60, etc.), as described in the DIN EN 100083 industry norm. Shafts, gears, armatures, sprockets and other components can all be hardened using this induction process.

The process is very demanding on the equipment and the inductor used. Ideal hardening results can only be achieved by perfectly matching a precisely controlled energy source with an optimum inductor design. eldec's experienced engineers custom design the induction coils to meet customer unique specifications, including single turn, two-turn, face-heating, clamshell, and clamp inductors. Every machine is completely inspected and tested to ensure optimum power and heat settings.

Heating directly with induction hardening

Induction hardening in Faridabad is a process in which the heat is generated directly in the work piece. The principal advantage of this type of heat treatment is that the material quickly reaches the desired temperature to produce hardened metal parts. With traditional heat treatments such as flames, ovens, or by convection, heat is applied to the part by heating up the surface layer. These methods take considerably longer and require significantly more energy to produce the desired hardness. Induction hardening, by contrast, offers extremely short heating times. It is a very effective and attractive method in the manufacturing of steel shafts, components, and other metal parts across a range of industries. Additionally, induction heating can be very precisely controlled via the power, frequency, and inductor geometry. This minimizes deformities in the workpiece and ensures the efficiency of the process.

How induction hardening works

The primary application of this induction method is the hardening of steel. One or many induction coils are used to generate and target an alternating magnetic field. This magnetic field produces eddy currents in the metal, which heat the workpiece up to the desired temperature. Immediately after heating, the component then goes through a quenching process using water, oil, or an emulsion. This cools the metal until martensitic transformation occurs, producing a hardened surface that is tougher than the base metal.

After quenching, the steel undergoes tempering, a low-temperature heat treatment process, to reach the desired hardness / toughness ratio. The maximum hardness of a steel grade obtained through the hardening process gives the material a low toughness. Treating the steel through tempering reduces the hardness in the material and increases its toughness.

The hardening depth in the work piece is controlled, very precisely, by adjusting the electrical power output of the induction machine and the frequency of the inductor / coil current. The thickness of the heated layer from the surface of the metal to some point below the surface is inversely proportional to the frequency of the applied alternating current. Higher frequencies produce thinner skins. Case hardening in Faridabad the surface of steel increases the wear resistance of the component without reducing the ductility of the bulk of the material. eldec offers energy sources with the latest converter technology in three frequency ranges:

• Low: 1 – 7 kHz
• Medium: 8 – 40 kHz
• High: 60 – 500 kHz

Induction hardening with SDF

With Simultaneous Dual Frequency, also known as SDF, eldec offers an additional method that is used especially for work pieces with complex shapes. A medium frequency is overlaid with a high one so that both act upon the material simultaneously at a uniform depth. This guarantees the component is heated at a consistent temperature across the entire part to ensure even surface hardness. This application is perfect for the process of manufacturing cogs and gears. Even though the top and bottom of the gear teeth are at different distances from the inductor, a smooth and precise hardness layer can be achieved.