Hybrid components, made of multiple materials, can meet the increasing demands for lightweight construction and functional integration in the automotive and aircraft industry. Hybrid semi-finished components are produced by applying a high-alloy cladding to a low-alloy base material before hot-forming and machining the workpiece. Throughout this process chain, workpiece deviations in the form of material distribution and material properties can occur that influence the component’s lifetime. This paper investigates whether such workpiece deviations can be detected within the process chain by analyzing process signals obtained from subsequent process steps. For this purpose, artificial workpiece deviations were introduced to hybrid semi-finished workpieces made of C22.8/X45CrSi9-3. Then, process signals during forming and machining were analyzed to determine their sensitivity to the artificial deviations. The results revealed that deviations in cladding size can be effectively monitored using signals from both forming and machining. Cladding position deviations can only be detected during machining, while forming signals are more responsive to detecting the introduced hardness deviations of approx. 100 HV0.1.
Laser hot-wire cladding, Cross-wedge rolling, Machining, Monitoring, Workpiece deviations
An ageing society and the emergence of new diseases are generating rapid growth in the healthcare industry in many industrialized countries. The use of AI can lead to an increase in performance while at the same time reducing costs. This is why the use of AI in the medical technology is continuously increasing, driven by the numerous benefits it brings, including
AI, Unsupervised Learning, Diagnostics
The Collaborative Research Center 1153 is investigating a novel process chain for manufacturing high-performance hybrid components. The combination of aluminum and steel can reduce the weight of components and lead to lower fuel consumption. During welding of aluminum and steel a brittle intermetallic phase is formed that reduces the service life of the component. After welding the workpiece is heated inhomogeneously and hot formed in a cross-wedge rolling process. Since the intermetallic phase grows depending on the temperature during hot forming, temperature control is of great importance. In this paper, the possibility of process-integrated contact temperature measurement with thin film sensors is investigated. For this purpose, the initial temperature distribution after induction heating of the workpiece is determined. Subsequently, cross-wedge rolling is carried out and the data of the thin film sensors are compared to the the temperature measurements after heating. It is shown that thin film sensors inserted into the tool are capable of measuring surface temperatures even at a contact time of 0.041 s. The new process monitoring of the temperature makes it possible to develop a better understanding of the process as well as to further optimize the temperature distribution. In the long term, knowledge of the temperatures in the different materials also makes it possible to derive quality characteristics as well as insights into the causes of possible process errors (e.g. fracture of the joining zone).
cross-wedge rolling, thin-film sensors, hybrid components, aluminum, temperature monitoring
The Collaborative Research Center 1153 is investigating an innovative process chain for the production of hybrid components. The hybrid workpieces are first joined and then formed by cross-wedge rolling. Pinion shafts were manufactured to investigate the behavior of the joining zone under increased complexity of the forming process. For this purpose, six types of workpieces produced by three types of joining processes were formed into pinion shafts. The reference process provides a shaft with a smooth bearing seat. It was found that the increased complexity did not present any challenges compared to the reference processes. A near-net shape geometry was achieved for the pinions made of steel.
hybrid components, cross-wedge rolling, hot forming, laser beam welding, LHWD welding
Progressive digitalization and new technologies have had a major impact on the development of artificial intelligence (AI) in recent years. Particularly for companies in the skilled trades sector, the time factor is taking on an increasingly changing customer behavior, more complex and demanding tasks, and other challenges, the time factor is playing an increasingly decisive role.
artificial intelligence, craft, guideline
A new process chain for the manufacturing of load-adapted hybrid components is presented. The "Tailored Forming” process chain consists of a deposition welding process, hot forming, machining and an optional heat treatment. This paper focuses on the combination of laser hot-wire cladding with subsequent hot forming to produce hybrid components. The applicability is investigated for different material combinations and component geometries, e.g. a shaft with a bearing seat or a bevel gear. Austenitic stainless steel AISI 316L and martensitic valve steel AISI HNV3 are used as cladding materials, mild steel AISI 1022M and case hardening steel AISI 5120 are used as base materials. The resulting component properties after laser hot-wire cladding and hot forming such as hardness, microstructure and residual stress state are presented. In the cladding and the heat-affected zone, the hot forming process causes a transformation from a welding microstructure to a fine-grained forming microstructure. Hot forming significantly affects the residual stress state in the cladding the resulting residual stress state depends on the material combination.
laser hot-wire cladding, cladding, hot forming, residual stress, tailored forming
Tailored forming is used to produce hybrid components in which the materials used are locally adapted to the diferent types of physical, chemical and tribological requirements. In this paper, a Tailored Forming process chain for the production of a hybrid shaft with a bearing seat is investigated. The process chain consists of the manufacturing steps laser hot-wire cladding, cross-wedge rolling, turning and deep rolling. A cylindrical bar made of mild steel C22.8 is used as the base material, and a cladding of the martensitic valve steel X45CrSi9-3 is applied in the area of the bearing seat to achieve the strength and hardness required. It is investigated how the surface and subsurface properties of the hybrid component, such as hardness, microstructure and residual stress state, change within the process chain. The results are compared with a previous study in which the austenitic stainless steel X2CrNiMo19-12 was investigated as a cladding material. It is shown that the residual stress state after hot forming depends on the thermal expansion coefcients of the cladding material.
Tailored forming, Residual stress, Laser hot-wire cladding, Deep rolling, Hybrid Components
The Tailored Forming process chain is used to manufacture hybrid components and consists of a joining process or Additive
Manufacturing for various materials (e.g. deposition welding), subsequent hot forming, machining and heat treatment. In
this way, components can be produced with materials adapted to the load case. For this paper, hybrid shafts are produced by
deposition welding of a cladding made of X45CrSi9-3 onto a workpiece made from 20MnCr5. The hybrid shafts are then
formed by means of cross-wedge rolling. It is investigated, how the thickness of the cladding and the type of cooling after
hot forming (in air or in water) afect the properties of the cladding. The hybrid shafts are formed without layer separation.
However, slight core loosening occurres in the area of the bearing seat due to the Mannesmann efect. The microhardness
of the cladding is only slightly efected by the cooling strategy, while the microhardness of the base material is signifcantly
higher in water cooled shafts. The microstructure of the cladding after both cooling strategies consists mainly of martensite.
In the base material, air cooling results in a mainly ferritic microstructure with grains of ferrite-pearlite. Quenching in water
results in a microstructure containing mainly martensite.
laser hot-wire cladding, cross-wedge rolling, hybrid components, cladding
Student job, Master thesis, Bachelor thesis, Project thesis, Internship
