Inside the QA facility of one of the giants of the fastener world
REYHER lets us in behind the scenes of how it approaches the vital job of measuring and testing fasteners and fixings…
Few fastener and fixing wholesalers can compete with the sheer scale of Hamburg-headquartered REYHER. The firm stocks more than 130,000 different products, fully automated warehouse logistics and 40,000 m² of space at its central location in the northern city. Naturally, the firm has in-depth and vigorous quality systems in place and the firm recently launched a video to showcase the journey fasteners and fixings go on through REYHER’s QA laboratories.
"From goods in and taking samples all the way through to the storage of tested goods, products in the QA lab undergo everything from manual thread inspection to hardness testing and screw joint analysis."
TESTING LABORATORY
The REM team (REYHER Engineering Management) is responsible for technical matters and Reyher’s in-house testing laboratory. The team educates its own material testers to extend the team and develop continuity and technical competence for the future.
Geometry control
The dimensions of parts are inspected using digital vernier callipers and digital external micrometres (among other instruments) connected to REYHER’s ERP system via an interface. A precision measurement system by ECM Datensysteme allows optical inspection and measurement of complex parts.
Tensile testing
At what point will a fastener break? REYHER’s tensile testing equipment (including Z20 and Z1200 ZwickRoell machines) determines the tensile strength, yield strength, elongation at break, deformation at break and test loads on fasteners. Tensile of forces up to 1,200 kN can be applied, with screws turned on a lathe in a standardised process to determine a wide range of characteristics.
Hardness testing
REYHER can apply standardised hardness measurements of fasteners with the use of Vickers, Brinell and Rockwell machines, determining the resistance of a material against the penetration of a test specimen which acts on it in a specific shape, force and time.
Low-load hardness testing
Low-load hardness testing serves to measure thin hardened layers. In the case of fasteners, this test is particularly important, for example in order to determine unacceptable carburisation or decarburisation after heat treatment processes. REYHER uses a hardness testing device with electromotive force control that is controlled directly via a PC workstation to clearly illustrate test results.
Spectral analysis
The chemical composition of materials can be determined through spectral analysis. REYHER does this with an arc/spark analyser from SPECTRO, shedding light on how products will behave, in terms of corrosion, for example.
Metallography/microscopy
REYHER’s impressive QC capabilities also see it able to examine products at a microscopic level, analysing the microstructure of metallic materials using powerful reflected light microscopes by ZEISS. This kind of analysis reveals grain sizes, heat treatment condition, surface defects and more.
Salt spray testing
Corrosion resistance is a key performance factor for multiple products and applications. Salt spray chambers (REYHER has two, with a total volume of 1,763 litres) expose samples to a fog of sodium chloride solution, covering them with a corrosive salt-water film to determine material corrosion.
Coating thickness measurement
Devices made by FISCHER are used to determine coating thickness and whether layer thickness is even, all of which impact on the corrosion resistance of a fastener. Different methods (X-ray spectrometric method and magnetic/magnetic induction method) are used depending on the material in question.
Screw joint analysis
The horizontal test bench tests torque/clamping force behaviour of screw joints and as a result the spread range of the friction coefficient is determined. REYHER uses the modern “ANALYSE System” from KISTLER to perform torque and/or preload tests of screws and nuts up to M48. Meanwhile, screw joint analyses in a vertical test bench are mostly performed in direct screw connections. KISTLER technology is also employed in these types of inspections.
Bending test stand
Determining the yield moments of fasteners is achieved with a bending test stand. The fastener is clamped at defined positions and torque is applied.