Automotive

 

Introduction

The automotive industry is an important global economic driver. Requirements and stresses on components from this sector are increasing daily. Topics such as driving comfort, service life or the environment are now more important than ever.
In order to meet these high demands, it is important that metallic components which are installed in large numbers in the automotive industry (engine blocks, shafts, cylinder heads, gears, etc.) are subjected to specific and correct heat treatment.
RÜBIG sees itself as a specialist in providing components with the right heat treatment according to their application profile in order to meet the high demands.

Parts

Drive shafts / Joints

These components transmit the torque from the gearbox to the wheels. A distinction is made between rigid and movable drive shafts, whereby movable shafts are also referred to as cardan shafts.
Above all, drive shafts are automotive components that require a high level of safety, as serious accidents can occur in the event of a breakdown during operation. In order to increase the service life of these components and thus counteract wear, they are heat-treated. Depending on the area of application and customer requirements, coordinated heat treatment processes are used here. Above all, Case Hardening R.CARB+®, from Vacuum Hardening R.VAC+® Vacuum Hardening process UDAK (Vacuum Carburizing) or Plasma Nitriding PLASNIT® as well as Gas Nitriding R.NIT+® are suitable.

Suspension

A wheel suspension serves as a connection between the vehicle body and the respective wheel and contains guide elements. They ensure safe driving, cushion road unevenness and dampen noise transmission. Parts of the suspensions are the wheel carriers, handlebars, joints, springs and shock absorbers.
To ensure a long component life, these components are heat-treated. The following procedures are particularly suitable here: Case hardening R.CARB+® (Case Hardening and Inert Gas Hardening) and Vacuum Hardening R.VAC+®.

Clutch parts

The clutch ensures that the appropriate torque reaches the wheels. Part of the clutch is the pressure plate, which functions as a friction system with the flywheel and the clutch disc. The clutch pressure plate is screwed directly to the clutch housing and after a gear change causes the engine torque to be returned to the shaft on the gearbox. A pressure plate in the clutch operates the clutch itself and is subject to high wear stresses.
Plate carriers are also part of the coupling, a distinction between inner and outer plate carriers. Good strength and toughness are indispensable due to the stresses to which these components are exposed.

The following heat treatment is suitable for this: Plasma Nitriding PLASNIT®.

Rocker arms

Rocker arms are used to change the direction of a force. In internal combustion engines, the rocker arm moves the intake and exhaust valves and functions like a rocker. The lever is exposed to high dynamic forces and thermal loads.
To improve the life and durability of the component, heat treatment is essential. The following methods are suitable for this: Gas Nitriding R.NIT+® and Plasma Nitriding PLASNIT® or Case Hardening R.CARB+® and Hard Coating PLASTIT®.

Crank shafts

Crankshafts convert linear movements of a piston into a rotary movement. They must therefore withstand the loads generated during flight operations and are exposed to both compressive and tensile forces as well as radial forces. Accordingly, it must be ensured that a crankshaft has sufficient bending and torsional strength and that the bearing points have a good load-bearing capacity.
A surface treatment of crankshafts may be necessary to increase the material strength in the surface layer and to improve the wear behaviour.
Suitable thermo-chemical processes are Gas Nitriding R.NIT+®, Nitrocarburising R.NIT+®, Plasma Nitriding PLASNIT® and Case Hardening R.CARB+®. The addition of nitrogen results in an increase in strength and a build-up of compressive stresses, which leads to improved load-bearing capacity of the crankshaft. During Case Hardening R.CARB+® the surface layer is carburised, which is mainly used in racing.

Bearings

Bearings are components that connect machine parts and slide or roll over each other. They transmit movements and transmit forces. A distinction is made here between plain and roller bearings.
In the automotive industry, ball, roller or needle bearings are subject to high loads. In the long run, this load leads to wear and thereby limits the service life of the parts.
The resistance generated can be reduced by adequate heat treatment, low-friction material combination and lubrication. The RÜBIG hardening techniques Gas Nitriding R.NIT+® and Plasma Nitriding PLASNIT® or Case Hardening R.CARB+® as well as Vacuum Hardening R.VAC+® increase the strength of the parts. Moreover, bearing rings can only withstand constant rolling of the rolling element without damage after heat treatment.
A surface coating can be used to minimise friction. The PLASTIT® Hard Coating processes are particularly suitable for this.

Gear hub

Gear hubs are machine elements that are pushed on shafts, axles or pins. In a vehicle, the wheel hub forms the centre of the wheel and rotates on its own axis. Since hubs are exposed to heavy loads, heat treatment serves to extend the service life of the component. Good wear and strength properties, which can be achieved by the following heat treatment processes, are particularly important here: Case hardening R.CARB+® (Case Hardening, Inert Gas Hardening) and Vacuum Hardening R.VAC+® (UDAK).

Camshafts

Camshafts control the intake and exhaust valves of internal combustion engines. Therefore, camshafts are exposed to high wear and contact loads as well as increased friction loads. A suitable combination of wear resistance, toughness and strength is essential for this. Due to the geometry (long shaft, small diameter), the component is at risk of distortion during heat treatment. Low temperature processes (<550°C) such as Gas Nitriding R.NIT+® and Plasma Nitriding PLASNIT® minimise the resulting heat distortion.

Valves

Valves seal the combustion chamber, a distinction is made here between intake valves that open the combustion chamber of the engine and exhaust valves that open and close the exhaust outlet. These are controlled by a camshaft. Valves operate under the influence of aggressive gases, extreme temperatures and are exposed to strong frictional forces. They are both thermally and mechanically stressed parts. Defective valves can lead to overheating and melting in the engine compartment.
Heat treatment is used to achieve high wear and corrosion resistance, high temperature resistance and scale resistance and thus significantly extend the service life of these parts. The following processes are suitable for this: e.g. Gas Nitriding R.NIT+® and Plasma Nitriding PLASNIT® or also Case Hardening R.CARB+® and Vacuum Hardening R.VAC+®.

Drive shafts

Drive shafts are required to transmit rotary movements and torques and to fix or mount rotating parts. Unlike axes, shafts transmit torque. In the automotive sector, for example, these are crankshafts, camshafts, cardan shafts, synchronised shafts and double cardan shafts.
Due to the high stress, a suitable and carefully executed heat treatment and material selection is indispensable. RÜBIG Hardening Technology offers heat treatment processes tailored to the component requirements in order to extend the service life of the parts.

Gearwheels / Planetary Gears

Gears are used to transmit the torque of a motor to the drive unit. The requirement for gears is that they must not shatter even under extreme loads. In order to be able to withstand shock loads or to be able to yield elastically in the event of abrupt torque increases, the teeth require both certain strength at the edge and toughness inside.

In planetary gears, several gears are installed in a rotating frame and orbit a centrally located sun gear. The sun wheel transmits the energy to the planet wheels. In principle, planetary gears serve as transmission stages, as transfer or summing gears or are part of an automatic transmission.

Heat treatment improves both the strength and the wear behaviour of the component. Planetary gear units are used for very high reduction ratios. This causes very high loads for the gears. These properties can be adjusted with the aid of specific heat treatment processes. In particular, Case Hardening R.CARB+® and Nitriding PLASNIT® and R.NIT+® are used here.

Cylinder heads

Cylinder heads are made of aluminium in modern engines. A cylinder head comprises inlet and outlet channels, the valve control for gas change processes, oil channels for valve train lubrication. In water-cooled engines, the coolant ducts are located in the cylinder heads, in gasoline engines the spark plugs and in diesel engines the injection nozzles and glow plugs. Since temperatures of over 250°C can be reached in the area of the combustion chamber, this can lead to thermal fatigue in the long term. Toughness and strength values play a decisive role in counteracting the high loads. These can be homogenised by suitable heat treatment. The RÜBIG ALU mainly offers T6 and T7 states for the heat treatment of aluminium castings. T6 and T7 states convince by the short throughput times with highest quality.

Services Heat treatment
Services of the Heat Treatment division at a glance: