# Influence of Different Base Materials on the Microstructure and Properties of Clad Rebar
## 1 Introduction  
Clad rebar is a new type of composite rebar with carbon steel as the base and stainless-steel coating as the outer layer. Clad rebar not only shows strong resistance to corrosion but is also less expensive (about one-third the cost of stainless-steel rebar). It can be widely employed in areas such as the oil industry, transportation, infrastructure, and marine engineering [1; 2; 3]. Currently, many researchers are investigating clad rebar. For instance, the United States-based company STELAX has proposed a production process of clad rebar based on iron filings. The iron filings are first stuffed inside stainless-steel pipes, and a strong bond is formed between the iron filings and stainless-steel pipes through procedures such as compaction, heating, and thermal recompression [4]. The above process successfully recycles the iron filings and effectively reduces the production cost of clad rebar. [PERSON] et al. used the Forge2007 software (Material Forming Research Center, Paris, France) to build a simulation model for the finish rolling of clad rebar and studied the influence pattern of different K2 groove forms on the clad contour. The results showed that the rebar prepared by rolling with a flat elliptical groove had the smallest range and variance in cladding thickness [5; 6]. [PERSON] et al. developed two different processes to prepare clad rebar, namely, spray deposition and electroslag remelting. Test results indicate that the properties of clad rebar rolled using these two processes satisfy the relevant regulations [7]. [PERSON] et al. simulated the heating, rolling, cooling, and other relevant processes of clad rebar by using a thermal simulation testing machine. The optimum performance of the clad rebar was achieved at a rolling temperature of 1000 \({}^{\circ}\)C and a downforce level of 50% [8]. [PERSON] et al. built a six-pass simulation model for the rough rolling of clad rebar with Mark and then optimized the process parameters. The results indicated that clad rebar rolled under micro-tension had a more uniform distribution of cladding profiles and a considerably smaller range of coating thickness [9]. [PERSON] et al. used the rhombus-rhombus-rhombus-square-elliptical-circular groove shape to prepare Q195/304 clad rebar and analyzed the properties of the clad rebar as well as the distribution conditions of various elements. The results showed that no cracks occurred on the composite interface after the tensile deformation of the rebar [10]. [PERSON] et al. investigated mainly the mechanical properties of clad rebar after corrosion. They first utilized an electrochemical work bench to conduct corrosion experiments on the clad rebar; they then performed tensile tests on the clad rebar after corrosion with the help of a universal testing machine, and finally, they used function fitting to construct a mathematical model depicting the relation between tensile properties and corrosion time. It was found that an increasing number of corrosion pits were formed on the surface of the rebar with increasing corrosion time. To ensure the proper functioning of rebars, the corrosion rate of clad rebars should be maintained below 13.9% [11]. [PERSON] et al. designed 27 groups of rolling process parameters for clad rebars using an orthogonal experiment method. They tested the tensile properties of the 27 groups of clad rebars by using a universal testing machine. The results indicated that clad rebar had optimal tensile properties at a rolling temperature of 1200 \({}^{\circ}\)C and a downforce level of 32% [12]. The types of base and clad materials have a strong influence on the properties of the composite steel materials and the states of the composite interface [13; 14; 15; 16; 17]. For example, base materials with poor properties could result in unsatisfactory mechanical properties of the composite steel materials. However, little research has been conducted on the choice of base or cladding materials for clad rebars.