The French Machinery Industry Technology Center (Cetim) has released a new type of steel for laser powder bed fusion (L-PBF) additive manufacturing. It is reported that the steel can be nitrided. According to Cetim, the new grade has been added to the list of steels used in AM, and the organization has used 33CrMoV12 steel for parts production, additive manufacturing through L-PBF, and R & D work on behalf of French manufacturers a part of.
The organization says that with its high carbon ratio and nitriding capacity, this steel has attractive mechanical properties and opens up new application possibilities, especially in the field of power transmission. It joins three steels that have been frequently used in L-PBF manufacturing: X2CrNiMo17-12-2 (316L) and X5CrNiCuNb16-4 (17-4PH) stainless steel and X2NiCoMo18-9-5 steel (martensitic 300).
Cetim explained that although these three steels are easy to weld due to their low carbon levels (about 0.05%), the 33CrMoV12 grade has a carbon content as high as 0.36%. Therefore, the powder of this material must be preheated before L-PBF, which makes the manufacturing process more cumbersome.
Cetim believes that although some AM systems have a preheating system, in most cases the preheating temperature is insufficient, about 200 ° C and below the required 500 ° C. To limit and eliminate this operation as much as possible, one solution is to specifically determine the laser fusion parameters.
The organization's research was conducted in conjunction with Volum-e, a French expert in polymer, metal prototyping and additive manufacturing. By fine-tuning the process parameters, the two partners stated that they were able to manufacture samples and displays in the steel under study through L-PBF.
It is reported that Cetim continued to work by carefully inspecting the parts, including: chemical analysis of materials, porosity, residual stress, effects of heat treatment on mechanical strength (tensile and bending), nitriding ability, fatigue strength, etc. The organization's evaluation of the study showed that 33CrMoV12 steel can be processed by L-PBF, which exhibits higher mechanical properties than those of the same layer steel, and due to its nitriding ability, its range of use includes heavy surface load components.