DD270141A1 - DEVICE FOR PRODUCING AND TESTING AXIAL SYMMETRIC SAMPLES FOR WELDABILITY AND LAMINATE RAKE - Google Patents

Abstract

The invention relates to a device for producing axially symmetrical, in particular sections of different materials existing samples and for testing these samples for welding suitability (hot and cold cracks), welding security (Sproedbrueche) and Lamellarrissneigung. The basic idea of the invention is to produce and test the cohesive compound in one and the same apparatus, thereby influencing the temperature and deformation regime as well as the design and production regime that decisively influences the production, its structures and the resulting mechanical-technological properties - And stress-induced stress state in a wide range quantitatively and reproducibly to vary and adjust. Fig. 1

Description

For this 1 page drawing

Field of application of the invention

The invention relates to a device for producing axially symmetrical, in particular sections of different materials existing samples and for testing these samples for weldability and Lamellarrißneigung.

Characteristic of the known state of the art

The weldability, defined in TGL14 913, is a very complex quantity, which is therefore subdivided into the sub-concepts of weldability and welding safety.

The weldability is preferably dependent on the material, the welding reliability of the material, the construction and manufacturing.

Weldability tests have the goal of determining the inclination of the material to hot and cold cracks (weldability) or the tendency of the component to brittle fractures (welding safety). With the ever increasing load of welded structures, the lamellar cracks turned out to be another phenomenon affecting weldability. These are cracks that occur in the case of a very large tensile load of the welded construction in the thickness direction.

To test the weldability, welding safety and Lamellarrißneigung a very large number of test methods and devices such. B.

Static tensile tests with uncarbored and notched specimens with a tensile stress resulting from an external load or from shrinkage forces,

Static bending tests with unnotched and notched samples,

- Impact bending tests,

- Falling weight tests and

- fracture mechanics investigations

developed. However, some require such a large test wall, that they have not been successful for this reason.

The big disadvantage of all test methods and devices is that

The temperature and deformation regime of the styrenic compound produced by heat and / or strain work can equally well be defined and reproducibly adjusted, as is the state of construction, stress and strain caused by the test,

The production of the integral connection and the testing of the welded connection requires various and very complicated devices,

- The tensile and shear stress, test temperature and stress rate required to test weldability, welding reliability ur, d of lamella inclination, can not be adjusted with sufficient combination, variation, accuracy and reproducibility.

Object of the invention

The aim of the invention is a device with which the weldability, welding safety and Lamellarrißneigung metallic materials can be determined with a lower cost of material, energy and working time, but with greater accuracy and reproducibility than before.

Explanation of the essence of the invention

The invention has for its object to develop a device with both the Heisteilung of axially symmetric samples, in particular sections of different materials existing samples, as well as a short time after completion of the welding process, i. at intervals of a few seconds, these samples can be tested for weldability, welding safety and lamella tendency without the need for instrument retrofitting or test re-tensioning and time-lapse re-clamping between sample preparation and testing. The device to be developed must at the same time be able to reproducibly simulate the temperature and deformation regime of conventional welding processes which are decisive during the phase of the sample preparation, reproducibly simulating its microstructure and the mechanical properties resulting therefrom - without actual use of these welding processes during sample preparation, and to quantitatively and reproducibly vary and adjust the state of construction, production and stress conditions during the test phase in a wide range

 According to the invention the object is achieved in that

- For the preparation of samples for testing for welding suitability and welding safety two sample parts of the material to be examined in each one Spanneinrlchtu aligned in a row are arranged so that face each two end faces, wherein at least one chip; ! Device mounted rotatably and driven and at least one clamping device in the axial direction and slidably arranged with an axial force can be acted upon.

- For the preparation of samples for testing for Lamellarrißneigung the sample of the material to be examined held in a stationary, non-rotatably mounted clamping device and the two weld studs of the same or similar material in alignment with the sample are arranged so that they sample with an end face to the Oher Touch - or underside, wherein both clamping devices of the Acschweißbolzen rotatably mounted and driven so that a clamping device with a left-handed and a clamping device with a clockwise torque are acted upon acted upon, that applied by the clamping device holding force is approximately zero, and that two clamping devices of the weld bolts are axially displaceable and arranged to be acted upon by an axial force.

The axial force acting on the two samples or weld bolts of cross-section A is a compressive force Fd, 20MPa £ F _d / AS 60MPa by friction welding during manufacture of the integral connection and a tensile force F ₁ , 0 when testing for hot and cold cracks, spall fractures and lamellar tears <F, S AR ₁ JT), wherein for generating a defined multiaxial stress state, means for superimposing the tensile force with a torque are provided. The rotational speed η (η in min ^-1 ) of the rotating clamping devices must satisfy the boundary condition 0.8 m / s SvS 1.6 m / s, where for the friction velocity v for the samples or the welding steels with a solid cross section of diameter d = 2 r (FIG. r in m) ν = 0.07 rn and for the samples with a hollow cross-section of the middle diameter d _m = 2r _m (r _m inm) v = 0.1 r _m n In the area of a friction zone, a temperature measuring device is arranged Further, the sample or Verschweißbolzenverkürzung with a Wegaufnehmor, the axial force with a load cell, the torque measured with a torque meter and the speed with a tachometer.

The samples for the weldability and welding safety tests, as well as the two weld studs and the sample for the lamellar tearing test, are surrounded by a container filled with a cooling or heating medium.

-3- 270 U1

exemplary

In the following, the invention will be explained more closely using the example of determining the lamellar tearing inclination. In the accompanying drawing shows

Fig. 1: the scheme of the device

From the semifinished product of the material to be examined disks 16 are produced with a circular cross section of diameter d. The disc 16 is firmly clamped in the fixed clamping device 17. Two weld-on studs 1 and 2 with a rotationally symmetrical full cross-section of the same material as the disks, which are turned to face each other at the end faces, are firmly clamped in a tensioning device 3 and 4. In the present example, the clamping devices 3 and 4 are rotatable and axially displaceable. The clamping device 3 is driven by a clockwise and the clamping device 4 by a clockwise torque. As a result, the on the disc 16 to cross friction moments have opposite direction, so that only a goringe holding force for the disc 16 must be applied by the clamping device 17.

When making the cohesive connection acts on the weld studs a compressive force and when testing the welded sample on Lamellarrißneigung a tensile force.

Through the work of the axial force and the frictional torque deform and heat the weld studs 3 and 4 and the disc 16 in Stoßflächenbereir.h.

In the area of a friction zone 5, the axial temperature distribution is determined with a thermal imaging camera 6. The sample shortening with a displacement transducer 7, the axial force with a load cell 8, the friction torque with a torque meter 9 and the speed with a tachometer 10 are measured remotely.

The measurement representation and processing is carried out with the color monitor 11, the analog-to-digital converter 12, the electronic image data memory 13 and the microcomputer 14th

After reaching the specified friction time, the conditions

- = const »0 At

^{Δ (Δ} ".constΦ0

At

ΔΜ At

= const Φ 0

must be satisfied, the rotating weld studs in the time t = 0.5s are decelerated to a standstill.

After cooling of the two joining rollers, the sample with a tensile force F ₁ , 0 <F ₁ S ARm (T), until the occurrence of lamellar cracks, recognizable ar. their terraced course, charged.

The material is lamellar polycarbonate if no such cracks have occurred until fracture.

By means of the container 15 filled with a heating or cooling medium, any technically sensible test temperatures can be set.

Claims (2)

1. A device for producing and testing axially symmetric samples on weldability and Lamellarrißneigung, in particular sections of different materials existing samples, characterized in that - For the production of samples for testing for welding suitability and welding safety two sample parts of the material to be examined in each clamping device (3; 4) are arranged in alignment one behind the other so that each face two faces, at least one of these clamping devices rotatably mounted and driven and in axially displaceable and can be acted upon by an axial force, - For the preparation of samples for testing on Lamellarrißneigung the sample (16) of the material to be examined held in a stationary, non-rotatably mounted clamping device (17) and the two weld studs (1, 2) of the same or similar material in each case a rotatable and axially displaceable mounted clamping device (3; 4) are arranged in alignment with the sample (16) so that they touch the sample (16) at the top or bottom with an end face, wherein both tensioning means (3; 4) are driven so that a Clamping device (3 or 4) with a left-handed and a clamping device (4 or 3) are arranged acted upon with a clockwise torque so that the stationary clamping device (17) to be applied holding force is approximately zero, and that the two clamping devices (3 4) are arranged acted upon with an axial force acting on the sample parts or weld studs (1, 2) acting from the cross section A Ax ialkraft during the production of the cohesive connection by friction welding a compressive force F _{d /} 20MPa SF _d / AS 60MPa, and when testing for hot and cold cracks, brittle fractures and lamellar tears a tensile force F ₂ , 0 <F ₂ S AR _m (T), is, are provided for generating a defined multiaxial stress state means for superimposing the tensile force F ₂ with a torque, - The speed η (η in min " ¹ ) of the rotating clamping devices (3 or 4) must satisfy the boundary condition 0.8 m / s SvS 1.6 m / s, wherein for the friction speed v for the sample parts or the weld studs (1; 2) with volume cross section of diameter d = 2r (rinm) v = 0,07 rn and for the sample parts with hollow cross section of mean diameter d _m = 2 r _m (r _m in m) ν = 0,1 r _m n, - In the region of a friction zone (5) a temperature measuring device (6) is arranged and further that the sample or Anschweißbolzenverkürzung with a position transducer (7), the axial force with a load cell (8), the torque with a torque meter (9) and the , Speed can be measured with a tachometer (10). Device according to claim 1, characterized in that the sample parts or the welding bolts (1; 2) and the sample (16) are surrounded by a container (15) filled with a cooling or heating medium.