Information relevant for the design of structure: Ferritic – Heat resistant high chromium steel X10CrAlSi25 Josip Brnic ⇑ , Goran Turkalj, Sanjin Krscanski, Domagoj Lanc, Marko Canadija, Marino Brcic Faculty of Engineering, Department of Engineering Mechanics, Vukovarska 58, 51000 Rijeka, Croatia article info Article history: Received 12 April 2014 Accepted 19 June 2014 Available online 30 June 2014 Keywords: High chromium steel Mechanical properties Creep tests Impact energy abstract In order to determine the behavior of the X10CrAlSi25 steel at room and elevated temperatures, a number of uniaxial tests were performed using a modern computer controlled material testing machine. Based on these tests, two types of their responses were considered. The first type of responses refers to the material properties presented in the form of engineering stress–strain diagrams. From these diagrams it is possible to derive and consequently to determine tensile strength, yield strength and a Modulus of elasticity. The second type of responses refers to creep behavior presented in the form of creep curves. Based on these curves, creep resistance of the considered material can be derived. Besides, the Charpy impact tests were performed with a Charpy impact machine to define Charpy impact energy as the basis for calculating fracture toughness. Considering tensile strength (584 MPa/20 °C) and yield strength (487 MPa/20 °C), it is visible that both of them are decreased when temperature is increased and fairly low strength levels at high temperature (tensile strength: 29 MPa/800 °C; yield strength: 26 MPa/800 °C) are measured. According to performed creep tests it is visible that this material does not belong to the materials resis- tant to creep. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction In modern design of structure, material selection is one of the key engineering factors. Many engineering applications can be sub- jected to high temperature conditions, or intended to be used in conditions with aggressive environment. When subjected to such environmental conditions, the material should meet some of the requirements as: high creep resistance, good creep strength, high tensile strength, ductility, high temperature strength, heat resis- tance, fatigue strength, resistance to high temperature corrosion and oxidation, etc. Moreover, since the material has to withstand and resist different conditions placed on the structures such as bridges, ships, pressure vessels and automotive structures, the choice of material must comply with the operating conditions and required lifetime of the structure. Accordingly, it is important to know the properties of material that need to comply with the conditions of service life. In that way, designers must know the dif- ferent types of materials, their properties, structures, manufactur- ing processes involved, etc. [1]. And while materials science is primarily concerned with the basic knowledge of materials, mate- rials engineering is concerned with the use of the knowledge of materials, i.e., how to transform materials into products. It is known that some of the facts, such as chemical composition, pro- cessing path and the resulting microstructure define the properties of the material [2]. Properties that depend on the microstructure are called structure sensitive properties (for example yield strength, hardness). Some of the processes such as cold rolling and hot roll- ing, are the means to develop and control the microstructure. How- ever, modern design is based on the criteria of optimal design, the use of finite element analysis of stress and strain and high capaci- tive computers. Namely, sometimes it is very difficult to find the exact response (for example stresses) of the considered structure subjected to specified loading condition, and in this case the struc- ture is approximated as an assembly of several pieces [3]. In addi- tion to this, depending on the level of the load, the response of the structure may belong to the elastic, plastic or elastic–plastic field. The stress-dependent part of the plastic deformation is referred to as slip [4]. Also, at certain load and at certain temperature, a new phenomenon may occur. In this case, the time-dependent part of the response of the structure, where strain increases at constant stress, i.e., strain influenced by the temperature is known as creep. Although in engineering practice many failures may occur, the structure is usually designed and manufactured with the assump- tion that it does not contain any failure. Commonly observed modes of mechanical failures in engineering practice can be men- tioned: force induced deformation, fatigue, creep, etc. [5]. Also, steel composition, cyclic and corrosion, poor design, defects in http://dx.doi.org/10.1016/j.matdes.2014.06.051 0261-3069/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +385 51 651 491; fax: +385 51 651 490. E-mail address: brnic@riteh.hr (J. Brnic). Materials and Design 63 (2014) 508–518 Contents lists available at ScienceDirect Materials and Design journal homepage: www.elsevier.com/locate/matdes