Autofrettage Machine up to 15000 bar. The Autofrettage process enables manufacturers to extend the fatigue strength and service life of components such as common rails, pump heads, (diesel) injection lines, and many other components in research and development as well as in series production.
Autofrettage Machine Enhancing Fatigue Strength for High-Pressure
Components up to 15000 bar
Autofrettage is a method for increasing the fatigue strength and durability of components that operate under high, pulsating pressures. During the autofrettage process, a component’s inner wall is pressurized beyond its elastic limit, creating a permanent compressive stress layer after pressure release. As a result, the autofrettaged zone of the DUT (device under test) enables improved use of the material’s structural properties, greater autofrettage pressure resistance, and extended component lifetime. The autofrettage method relies on the interaction between a plasticized inner zone and an elastically deformed outer zone. Therefore, under high autofrettage pressure, the interior becomes plastically deformed. When the pressure is released, the inner wall remains in residual compression, preventing crack initiation and delaying fatigue failure.
For high-pressure components in fuel systems, hydrogen applications, hydraulic equipment, and pressure vessels, autofrettage is a decisive factor in achieving long service life and operational safety.
As a result, engineers can:
- Increase fatigue life under cyclic pressure loading
- Improve burst pressure margins
- Reduce crack initiation risk
- Optimize wall thickness and component weight
- Enhance overall lifecycle reliability
Applications of the Autofrettage Process and High-pressure Strengthening Process
Autofrettage is widely used in high-pressure technology, particularly for:
- Common rail systems and fuel injection lines
- High-pressure connectors, cross fittings, and pump heads
- Hydraulic pump housings, liners, and jackets
- High-pressure nozzles
- Thick-walled pressure vessels
- Hydrogen pressure components
- Defense-related components, such as cannon tubes
- COPV tanks (water autofrettage up to 1,050 bar // also known as proof pressure test)
Engineering Principle: Controlled Residual Stress Generation
Autofrettage is not simply the application of high pressure. It requires:
- Precise calculation of autofrettage pressure based on material yield strength
- Defined pressure ramp profiles
- Controlled dwell times
- Accurate pressure measurement and closed-loop control
- Safe containment of extreme pressure levels
During the process:
- The inner wall plastically deforms.
- The outer wall remains elastically stressed.
- After unloading, the elastic recovery of the outer zone compresses the inner zone.
The resulting residual compressive stress significantly reduces tensile stress during operation, the primary driver of fatigue cracks. For components exposed to millions of pressure cycles, this stress redistribution is critical.
Autofrettage by Poppe + Potthoff Maschinenbau
Poppe + Potthoff Maschinenbau designs and manufactures high-precision autofrettage machines for industrial applications requiring extreme pressure stability and reproducibility.
Our autofrettage machines are engineered for:
- Autofrettage pressure levels up to 15000 bar
- Exact pressure ramp and dwell time control
- High-pressure stability and repeatability
- Automated or manual loading concepts
- Full process monitoring and data logging
- Integration into automated production lines
- (ATEX-compliant execution when required)
Unlike generic high-pressure test rigs, our autofrettage machines are specifically designed for controlled plastic deformation processes. This ensures consistent residual stress distribution and long-term process reliability.
The introduction of the China 7 emission standard will drive demand for high-pressure test. Learn more in our recent blog post.
Exemplary Test Standard: SAE International Prestressing (Autofrettaging) of Hydraulic Tubing Lines AIR1379
Discover More: Autofrettage Machines
Improve material strength and lifespan by up to 30% with high-pressure autofrettage up to 15,000 bar. Perfect for common rails, injector lines, and small volume defense applications. Learn more about our solutions below!
Multipurpose Autofrettage
Due to its high variability, the Universal Autofrettage is ideal for research and development purposes as well as for smaller series production. It increases the fatigue strength of high-pressure components such as pipes, lines, valves, rails, pump heads, sensors and other pressure vessels.
For variable geometries
Components with different geometries can be flexibly autofrettaged on this system. The conversion is carried out by changing the device. The Autofrettage parameters are freely programmable and editable.
Pressure intensifier
The pressure intensifier consists of a drive and a high-pressure part. The hydraulically-driven pressure converter also acts as a mediator.
Performance Data
Common Rail Serial Production Autofrettage
The autofrettage machine is equipped with a hydraulic pressure intensifier and consists of two subassemblies that are combined into a single compact rig. The pressure generation system (hydraulic intensifier) and the electric control cabinet are installed on one side of the rig. The other side is designed as a test chamber. Further, an automatic door is installed in front of the chamber, while a safety window in the protective door allows for observation of the component. The protective door is secured and is programmed to not be opened during the autofrettage process; making it a very safe rig.
Performance Data
Autofrettage Test Bench for Diesel Fuel Injection Lines
Maximize durability and performance with our Autofrettage machine, designed specifically for high-pressure diesel injection lines. This fully automated autofrettage bench performs precise autofrettage using programmed inreasing pressure with a hydraulic pressure intensifier, ideal for serial production environments. The system supports multiple injection line types and can be reconfigured quickly via interchangeable tooling.
Efficient Series Processing — Up to 10 Lines at OnceA Our autofrettage machine features a front-loading protective door for safe and easy manual insertion of components. However, in the days of automation a loading by a robot is possible. Up to ten lines can be processed in parallel, significantly increasing throughput. The integrated control panel allows operators to freely program the autofrettage pressure and monitor all relevant test parameters in real time.
Performance Data
Autofrettage Rig for Fuel Injection Lines
The diesel injection line autofrettage system is an independent unit for the autofrettage of diesel injection lines up to 8,000 bar. Most Poppe + Potthoff Autofrettage rigs can be upgraded to a 10000 bar and 12000 bar autofrettage machine, as well as extended to a multi-chamber system. Therefore, if your production ramps up, the machine can be equivalently adapted. This uniquely developed autofrettage machine is a great starter system, as it can be gradually increased from one chamber to two, and in some cases up to 6.
Performance Data
Autofrettage for Prototypes and Development
The Autofrettage system is ideal for research and development purposes. The rig allows high flexibility in terms of components that can be autofrettaged. Although limited for autofrettage on high quantities the rig is ideally placed in labs working on improving fatigue strength and material composition of new components. The Autofrettage pressure is freely programmable to fit customers’ requirements per each DUT. The control panel is located at an ergonomic height for operators and all relevant data is displayed to the operator and can be quickly edited at any time.
For example, it is possible to convert the system from a rail device to a pump head device. The system thus allows the autofrettage of various components and can be integrated into research and development as flexibly as possible. Even a small production can be supported with the system.
Performance Data
Autofrettage & Proof Pressure Test Stand for COPVs
Our Autofrettage and Proof Pressure Test Stands are designed for composite overwrapped pressure vessels (COPVs) and other high-pressure containers. Using water as the test medium, these systems enable precise autofrettage and pressure hold procedures to validate strength, enhance durability, and extend the structural life of pressure vessels.
Learn more in our blog post here.
Performance Data
Testing as a Service
At Poppe + Potthoff we offer autofrettage in various pressure ranges and for many components as a service. Whether for research and development or serial production, please contact us with your testing requirements for a non-binding offer.
Frequently Asked Questions — Autofrettage
Technical questions about the autofrettage process, our machines, and services — answered by our engineering team.
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Autofrettage is a metal pre-stressing process used to extend the fatigue life and pressure resistance of thick-walled, high-pressure components. The component’s inner wall is pressurised beyond its material yield point, causing the inner zone to plastically deform. When pressure is released, the elastic recovery of the outer wall places the inner surface under residual compressive stress. This compressive layer counteracts tensile stresses during operation — the primary driver of fatigue cracks — significantly extending service life under cyclic pressure loading.
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Autofrettage is most commonly applied to common rails and diesel injection lines, high-pressure pump heads and housings, cross fittings and connectors, hydraulic cylinders and pressure vessel liners, hydrogen storage components and tank fittings, and defence-related components such as cannon barrels. Any thick-walled component subjected to high, pulsating internal pressure can potentially benefit from the process.
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The required autofrettage pressure depends on the material yield strength and wall geometry of the component. In practice, pressures typically range from around 3,000 bar for lower-grade steel components up to 15,000 bar for ultra-high-pressure applications such as diesel common rails and hydrogen pressure vessels. Poppe + Potthoff autofrettage machines cover the full range from standard to extreme pressures.
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A pressure test — such as a burst test or proof pressure test — verifies whether a component can withstand a defined pressure without failure. It is a quality control or validation step. Autofrettage, by contrast, is a manufacturing process that actively changes the component’s internal stress state to improve its mechanical properties. The component is intentionally taken beyond its yield point. The two processes are complementary: autofrettage is performed during production, pressure testing validates the result.
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Fatigue life gains of 30% or more are commonly achieved in common rail and injection line applications. For components with bore intersections or stress concentrations, the improvement can be substantially higher. Autofrettage also allows engineers to achieve the same fatigue performance with reduced wall thickness, which has weight and cost implications for series production components.
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Autofrettage is used wherever components must survive millions of high-pressure cycles. Primary industries include automotive (common rail diesel and GDI fuel systems), hydrogen technology (storage tanks, valves, fittings), hydraulic engineering, aerospace (actuator housings, hydraulic lines), oil and gas (downhole tools, wellhead components), and defence (cannon barrels, weapon systems). R&D laboratories also use autofrettage to explore material limits and validate new component designs.
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Yes. Poppe + Potthoff offers autofrettage as a contract service at our facility in Nordhausen, Germany. This is suitable for prototype validation, small-series production, or applications where investment in dedicated equipment is not yet justified. Our team advises on the appropriate autofrettage pressure for your specific component and material, and provides full process documentation. Contact us with your component specifications to receive a quotation.
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Lead times for standard autofrettage machine configurations are typically 16 to 24 weeks from order confirmation. Highly customised systems — such as multi-chamber serial production lines with full automation and robot loading — may require longer depending on scope. Our engineering team provides a detailed technical consultation and project timeline before any commitment is required.
Test RIGS and Applications–
Accurate and reliable
As a specialist in pressure testing technology and test rigs, Poppe + Potthoff Maschinenbau supports the development and production of extremely resilient components made of various materials – especially for automotive, shipbuilding and mechanical engineering as well as fluid and the medical industry. We offer individually designed test benches such as burst pressure test rigs, pressure cycle test benches, leak test systems, functional test rigs and autofrettage systems.
Pressure change test stand with vacuum testing
Subject cooling systems of ECUs, PTC heaters, high-voltage coolant auxiliary heaters, ACDC and DCDC converters, and other media-carrying components to pressure tests while controlling the ambient and media temperature of, for example, water-glycol at temperatures from -40 °C to 140 °C.
Function test stand: battery simulation under the influence of temperature
For functional testing of media-carrying components, a temperature-controlled volume flow (e.g. 30l/min) can be generated with the Poppe + Potthoff test benches. In addition, a component from e-mobility can be energized if required.
Leakage test stand
Poppe + Potthoff leak test stands can be used to test various components and assemblies for leaks by means of a pressure drop. Depending on the test requirement, our systems can be designed including vacuum unit and low pressure or high pressure module for optimal leak testing. In addition, Poppe + Potthoff offers e.g. bubble tests in a water bath / underwater tests with air and gas.
Bursting pressure test rig < 200 bar
To prove the quality of media-carrying components, hose lines, pipes, pressure vessels and other components are pressurized until they burst.
Bursting pressure test rig < 200 bar
A flexible and expandable system for performing autofrettage on various components such as common rails and pump heads up to 12,000 bar.
Compressed air booster
Poppe + Potthoff Maschinenbau GmbH supplies compressor units and pressure control systems up to 400 bar. We offer ready-to-connect units to increase the existing pressure for pneumatic and hydraulic applications. This allows the performance of already existing plants to be expanded flexibly and efficiently.
Test bench for H2 components
We offer pressure testing equipment for the development and validation of hydrogen and nitrogen components. The focus is on test benches in the area of pressure cycling, burst pressure testing, and hydrostatic strength testing.
1050 Bar Helium / Nitrogen / Hydrogen
A leak test bench equipped with a pressure module up to 1050 bar, an optional integrated climate chamber and a gas sniffer (e.g. Inficon) to detect leakage on H2 components such as ontank valves, hoses, pipes, fittings, regulators, valves and fuel cell components.
Automotive
Automotive testing involves a wide range of tests. Poppe + Potthoff Maschinenbau supports the industry with state-of-the-art pressure test benches, autofrettage systems and functional test benches.
Aerospace
Test systems from Poppe + Potthoff Maschinenbau put fluid systems and components for aerospace applications to a tough test. In the service life test, they undergo millions of pressure load cycles to simulate the service life of a component.
Home Appliances
Household appliance manufacturers are aware of the importance of ensuring that their media-carrying components are leak-proof from day one and that components can withstand a pressure load higher than the operating pressure. Poppe + Potthoff Maschinenbau supports the industry with various pressure testing systems.
Medical Technology
Test benches for medical technology components from Poppe + Potthoff Maschinenbau put a wide variety of components to the test. Reliable, repeatable and accurate pressure tests and test processes ensure the quality of a component during research and development.
Shipbuilding
Marine engines are composed of components that are exposed to high pressures and require pressure testing of any kind. Cooling systems, pumps and valves of marine engines are exposed to pressure and are tested for their load capacity with pressure test benches from Poppe + Potthoff.
Oil and gas
Various components from the oil and gas industry can be tested on pressure test benches from Poppe + Potthoff. Drill pipes, tubes and (gas) valves are components that are exposed to changing pressure and temperature conditions and require pressure testing to ensure quality and safety.
Contact Us
Our experienced technical sales team will help you implement your project and find a solution tailored to your specifications and requirements. We are represented internationally and can support you and your company worldwide. Our team has completed hundreds of projects many of which involved supporting test facilities with identical equipment. P+P Maschinenbau is your internationally trusted partner.
Expertise, excellent knowledge of the market and affinity for our products guarantee our success.