Study On Microsture And Property Of Fe-based Coating With In-situ Strengthening Phases On 304 Stainless Steel By Laser Cladding

Stainless steel is widely used in industry in various fields because of good mechanical properties and excellent corrosion resistant performance. However some disadvantages limit the scope of use, such as lower hardness, lower wear resistance and so on. Ceramic materials are service ideal material under harsh working environment that high temperature, abrasion, corrosion and etc. Because they have the properties that the excellent high temperature mechanical properties, high hardness, antioxidation, corrosion resistance, wear resistance and etc.But generally ceramic materials have poor toughness. Therefore, our project put forward the idea that we can generate iron base coating which has ceramic reinforced phase in the stainless steel surface by means of laser cladding technology, which can synthesize their excellent performance to modify the surface of stainless steel. Using optical microscope(OM), scanning electron microscopy(SEM), electron microprobe(EPMA), X-ray diffraction(XRD), micro vickers hardness tester, such as electrochemical workstation instrument on the microstructure and mechanical properties of cladding layer,characterization analysis research reinforced rigid relative ratio of powder and the influence law of microstructure and mechanical properties of laser cladding coating and the microcosmic mechanism, Finally we prepared the excellent coating performance in the surface of 304 stainless steel in order to expand the scope of its use. Experimental results are as follows:(1)Using laser cladding technology, we prepared cladding layer that combination good and macro morphology good in the surface of 304 base material. By testing the performances of hardness and electrochemistry We found that the new preparation of the base material which have cladding layer have been improved obviously in the two aspects.(2)The specimen is prepared with mass fraction of 5%, 10%, 20%, 10%of titanium iron powder and graphite with nitrogen as the response and protective gas, newly created Ti(C, N) and Fe- N hard phase are found in the cladding layer, and the mass fraction of 10% shows optimum properties with the hardness peak is twice as great as base material,corrosion resistance is 1.43 times of the base material.(3)The specimen is prepared with mass fraction of 10%, 20%, 10% of titanium iron powder, boron iron powder and graphite, and argon as shielding gas, newly created Cr B, Fe Ti, Cr- Ni- Fe- C, Cr O0.87 phase are found in the cladding layer and the cladding layer with mass fraction of 30% is the best, its hardness is 2 times of the base material, corrosion resistance is 1.88 times of the base material.(4)The specimen is prepared with mass fraction of 10%, 20%, 10% of titanium iron powder, and B4 C powder, argon as shielding gas, newly created the Cr B, Ni4B3, Fe Ti, Cr-Ni-Fe-C, Cr O0.87 phase are found in the cladding layer and the cladding layer with mass fraction of 30% shows the best performance, its peak of hardness is 2.6 times of the base material, and corrosion resistance is 2.08 times of the base material.