Phosphorus in Sintered Steels: Effect of Phosphorus Content and P Carrier in Sintered Steel Fe-C-P

Abstract

Phosphorus as an alloy element is quite common in powder metallurgy, the contents industrially used being markedly higher than those present in wrought steels. In this study, the influence of phosphorus addition through different P carriers was investigated. PM steels of the type Fe-0.7%C-x%P (x = 0.0 … 0.8%) were manufactured by pressing and sintering in H2. It showed that Fe3P is the best phosphorus carrier, resulting in fine and regular microstructure and in high impact energy data at 0.3 … 0.45%P while red P and also Fe2P showed a tendency to agglomeration, with resulting secondary porosity. At high P levels the mechanical properties tend to drop, for the tensile strength at P > 0.60%P while for the impact energy the threshold is 0.45%P. The dimensional behaviour of Fe-C-P can be related to PM aluminium alloys, expansion by transient liquid phase being followed by shrinkage by persistent liquid phase, at least at higher temperatures. In contrast to the dimensional behaviour, degassing and reduction is hardly affected by the phosphorus content.

Phosphorus in Sintered Steels: Interaction of Phosphorus with Mo

“…The manufacturing route followed the procedure described e.g. in [21]: Starting powders were iron powder grade ASC 100.29, prealloyed Fe-Mo powder Astaloy Mo (Fe-1.5%Mo), both from Höganäs AB, and natural graphite Kropfmühl UF4 (purified grade, ash content <1%). Mo was added as fine elemental powder <32 µm (Plansee SE), and Fe3P was chosen as P source (supplied by MIBA Sinter Austria GmbH).…”

“…The properties obtained are listed in Tables 1-4; selected diagrams ( Fig.1) show the relationships between properties and the P content (for the Mo-free steels see [21]). The scatter of the individual values was fairly low, in the range common for sintered steels, except for the explicitly brittle specimens for which wide scatter was encountered both in tensile and impact testing.…”

Plasma processing of Fe-P/rGO powder for making robust wear resistance and anticorrosion coating over mild steel

“…Archaeological iron contains phosphorus in the range of 0.05-0.50 wt%, which is much higher than those found in modern steels (less than 0.02 wt%) [7,8]. The DIP has withstood inthe environment for over 1600 years and had an average composition of about 0.25 wt% phosphorus and 0.15 wt% carbon [9]. Phosphorus was considered as a deleterious element in modern steel making until 1939, when Dr Fritz Lenell found it to be a functional alloying additive in ferrous powder metallurgy.…”

Easily Sinterable Low-Alloy Steel Powders for P/M Diamond Tools

“…A moderate sintering temperature is an important characteristic of a matrix powder because exposure to 1120 • C, typical in ferrous operations [7,8], may degrade strength and impact toughness of diamond crystals [9]. The matrix material should also meet some other application criteria, such as high hardness and yield strength, to improve the matrix capacity for diamond retention [9,10], as well as toughness and resistance to abrasion [2,9].…”

“…Therefore, these three rapid diffusion paths became the most important powder design considerations. In all cases, phosphorus was used due to its potent hardening of iron and stabilisation of the bcc crystal structure [8]. Nickel, copper and tin were selected as additional alloying elements in order to stabilise austenite (Ni, Cu) and form a liquid phase (Sn).…”