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As a new type of structural-functional material developed in recent years, steel foam has the advantages of high specific strength and specific stiffness, high specific surface area, light weight, energy absorption and shock absorption, porous filtration, electromagnetic shielding and biocompatibility. It has a broad application prospect in aerospace, automobile, shipbuilding, civil engineering, heat dissipation and heat insulation, catalysis and filtration, electromagnetic shielding, biomedical engineering and other fields. In this paper, the research and development situation and existing problems of new steel foam are reviewed, and the preparation process, structure , performance characteristics and application fields of steel form are introduced, including the advantages and disadvantages of the existing preparation process, cell structure characteristics, mechanical properties （yield strength, elastic modulus, energy absorption value）, physical properties （heat dissipation and insulation, sound absorption and insulation, electromagnetic shielding）, biological properties and application of steel foam. The existing problems of steel foam and the limiting factors of its industrial development and application are analyzed. In general, the existing research has proved the feasibility of steel foam development and application as a light-weight high strength structural material and a special functional material, and pointed out the technical and theoretical research work to be carried out in the future.

In order to fabricate steel foams with high porosity,uniform pore structure and high-performance, steel foams with different porosities and cell sizes were fabricated by a sintering-dissolution process using 316L stainless steel powder as raw material and CaCl2 as pore forming agent, and steel foam-sandwich panels were fabricated by physical bonding. Three-point bending tests were carried out to explore the bending performance of steel foam and steel foam-sandwich panels. The influence of the porosity and cell size of foam sample on the bending load was analyzed and discussed,and the bending strength of steel foam -sandwich panel was compared with steel foam sample. The results show that the bending deformation of steel foam is started at the weakest cell wall firstly,then the cracks are initiated and propagated,eventually the macroscopic fracture is caused. For steel foam-sandwich panels,the maximum load is reduced from 2345 N to 1254 N when the porosity is increased from 69.4% to 82.5%,whereas the maximum bending load of steel foam-sandwich panels is increased by 15%-43% with the same porosity. When the cell size is increased from 1.9 mm to 3.9 mm and the porosity is about 73%,the maximum bending load is reduced from 2070 N to 1528 N,whereas the maximum bending load of steel foam-sandwich panels is increased by 15%-28% with the same pore size. Under the same porosity and pore size,the steel foam-sandwich panels have excellent resistance to bending at least 15% higher than the steel foam.