VŠB-Technical University of Ostrava , Czech Republic, department of Material engineering .

1. VŠB-Technical University of Ostrava , Czech Republic, department of Material engineering. EPNM-2010MECHANICAL PROPERTIES OF SANDWICH MATERIAL STEEL Cr18Ni10 + Ti AFTER EXPLOSIVE CLADDING Dmytro OSTROUSHKO1), Lubomír ČÍŽEK1) Zygmund SZULC2), Robert BANSKI2), Rafal MOLAK 2) 1)VŠB-TU Ostrava-CR, 2)Explomet Opole-Pl ., 2)Politechnika Warszawska-Pl

2. Introduction Metal surface protection has a significant role for materials applied in corrosion medium. Usuallymaterialused in the case of heavy products are very expensive. That is why a thing layer from this material is applied on the surface of basic material. One of methods used for creating such sandwich materials is explosive welding application.

3. Background : • Method of explosive welding became recently very popular and is frequently used, as it brings about many advantage. • Use of this method considerably reduces material costs and makes it possible to join materials, which cannot be otherwise joined together (e.g. Ti – steel, Cu alloys – steel and others).

4. Objective : Aim of my work is to identify the characteristics and behavior of materialsTi+Cr18Ni10 steelafter Explosive Cladding used in heat exchanger in the chemical equipment.

5. Methodology :preparation of materials for joining Saving explosives for the top sheet followed eplosion Saving sheet metal base

6. Samples for the fatiguetest The samples without heat treatment , (was marked - VS) and the samples after heat treatment - annealing at temperatures of 600 ° C (was marked - TZ). Time held at the isothermal temperature was 1.5 h with subsequent cooling in air. The samples were taken by mechanical cutting in order to prevent change of micro-structure of the material. The samples dimension was 12 x 10 x 100 mm

7. F Steel Ti L Fatigue tests were performed on the fatigue testing machine MTS (material test sistem) type 810 at the Technical University “Politechnika Warszawska”. Testing rods were subjected to load by a three-point bending. schematically shown in this figures Length of the tested part of the fatigue test rod L was identical in all the samples – namely 80 mm

8. Structuressamplesin etching state Micrograph of the stainless steel The grain size 45.3 m without the HT The grain size 35.2m with the HT Micrograph of the titanium matrix The grain size 18.6m without the HT The grain size 19.2m with the HT

9. VICKERS microhardness The blue line – samples without HT The red line – samples with HT

10. Results of fatigue test Ti + steel(CrNi)after HT Ti + steel(CrNi) without HT

11. Wöhler curve Wöhler curve of samples without HT Wöhler curve of samples with HT

12. Samples after fatigue test samples without HT after fatigue test samples with HT after fatigue test In the samples without HT the crack at lower stresses propagates right to the basic material, and at bigger loads the crack propagates only to the weld, and then continues to propagate along the welded joint . Situation in the sample with HT at higher stresses is the same as in the sample without HT. In lower stresses the crack does not propagate into the basic material as distinctly as in the sample without HT.

13. Conclusion: In collaboration with the company EXPLOMET the following materials were joined Ti + steel CrNi(18/10), including control of quality of the joined plates. The determination of micro-hardness are revealed that in the zone of the joint a deformation of materials occurs. As we foundout the sample with heat treatment have higher service lifetime as the sample without heat treatment,which are very positive for this component employed in chemical equipment. More detail observations of these particles will be focused in future works.

14. Thank you very much for your attentionAcknowledgement:The authors are grateful to the Ministry of Education of Czech Republic for financial support of the project MSM 6198910015. Czech Republic – Poland co-operation was realized with aim of project Interreg IIIa.