Microstructure and wear resistance of spray-formed supermartensitic stainless steel

Abstract

Since the early 90's the oil industry has been encouraging the development of corrosion and wear resistant alloys for onshore and offshore pipeline applications. In this context supermartensitic stainless steel was introduced to replace the more expensive duplex stainless steel for tubing applications. Despite the outstanding corrosion resistance of stainless steels, their wear resistance is of concern. Some authors reported obtaining material processed by spray forming, such as ferritic stainless steel, superduplex stainless steel modified with boron, and iron-based amorphous alloys, which presented high wear resistance while maintaining the corrosion performance 1,2 . The addition of boron to iron-based alloys promotes the formation of hard boride particles (M 2 B type) which improve their wear resistances [3][4][5][6][7][8][9] . This work aimed to study the microstructure and wear resistance of supermartensitic stainless steel modified with 0.3 wt. (%) and 0.7 wt. (%) processed by spray forming (SF-SMSS 0.3%B and SF-SMSS 0.7%B, respectively). These boron contents were selected in order to improve the wear resistance of supermartensitic stainless steel through the formation of uniformly distributed borides maintaining the characteristics of the corrosion resistant matrix. SF-SMSS 0.7%B presents an abrasive wear resistance considerably higher than spray-formed supermartensitic stainless steel without boron addition (SF-SMSS).

Wear resistant coatings of boron-modified stainless steels deposited by Plasma Transferred Arc

“…In abrasive wear tests the matrix and its carbon content play a significant role, decreasing worn volumes with increasing carbon content [24]. Comparing literature results of dry sand/rubber wheel [16,17], the worn volumes of specimens obtained by spray forming with the same composition are nearly in the range of PTA. Spray forming led to slightly higher abrasive resistance due to the more homogeneous distribution of boride particles and the finer equiaxed grains achieved [17,25].…”

“…The substrate hardness was significantly lower at approximately 237 ± 5 HV. The supermartensitic matrix is harder than the superduplex one [16]; nonetheless, considering the difference in the boride phase fractions, these particles were obviously responsible for the difference in hardness of the coatings. Fig.…”

“…Recently, the modification of a commercial supermartensitic stainless steel with small boron addition prepared by spray forming was studied by Zepon et al [16,17]. The authors reported a significant increase in wear resistance due to the formation of M 2 B-type borides.…”

Diffusion Control and Metallurgical Behavior of Successive Buttering on SA508 Steel Using Ni–Fe Alloy and Inconel 182

“…The a-Fe could not really exist in such chemistry, and therefore, the presence of martensite was confirmed with XRD in buttering deposit. Figure 10 shows the XRD peaks of c(Fe, Ni) austenite with different diffracted planes in buffer and buttering layer (encircled section for test), while a' with different diffracted planes [33] was also present in deposit which confirms the presence of martensite. Figure 11a, b shows the microstructure of Inconel 182 in fourth layer in as-buttered and 450°C thermally aged condition, respectively.…”

Influence of Heat Treatments on the Impact Toughness of a Ti-stabilized 12%Cr Supermartensitic Stainless Steel

“…According to Rodrigues et al 2 TiC fine carbides promote the refinement of the microstructure and increase the mechanical properties. Boron addition refined the microstructure and increased the hardness and wear resistance by M 2 B precipitation 3 . The mechanical properties of martensitic steels are adjusted by quenching and tempering heat treatments.…”