Investigation of the Properties of 316L Stainless Steel after AM and Heat Treatment

Additive manufacturing, including laser powder bed fusion, offers possibilities for the production of materials with properties comparable to conventional technologies. The main aim of this paper is to describe the specific microstructure of 316L stainless steel prepared using additive manufacturing. The as-built state and the material after heat treatment (solution annealing at 1050 °C and 60 min soaking time, followed by artificial aging at 700 °C and 3000 min soaking time) were analyzed. A static tensile test at ambient temperature, 77 K, and 8 K was performed to evaluate the mechanical properties. The characteristics of the specific microstructure were examined using optical microscopy, scanning electron microscopy, and transmission electron microscopy. The stainless steel 316L prepared using laser powder bed fusion consisted of a hierarchical austenitic microstructure, with a grain size of 25 µm as-built up to 35 µm after heat treatment. The grains predominantly contained fine 300–700 nm subgrains with a cellular structure. It was concluded that after the selected heat treatment there was a significant reduction in dislocations. An increase in precipitates was observed after heat treatment, from the original amount of approximately 20 nm to 150 nm

Investigation of the Properties of 316L Stainless Steel after AM and Heat Treatment

Additive manufacturing, including laser powder bed fusion, offers possibilities for the production of materials with properties comparable to conventional technologies. The main aim of this paper is to describe the specific microstructure of 316L stainless steel prepared using additive manufacturing. The as-built state and the material after heat treatment (solution annealing at 1050 degrees C and 60 min soaking time, followed by artificial aging at 700 degrees C and 3000 min soaking time) were analyzed. A static tensile test at ambient temperature, 77 K, and 8 K was performed to evaluate the mechanical properties. The characteristics of the specific microstructure were examined using optical microscopy, scanning electron microscopy, and transmission electron microscopy. The stainless steel 316L prepared using laser powder bed fusion consisted of a hierarchical austenitic microstructure, with a grain size of 25 mu m as-built up to 35 mu m after heat treatment. The grains predominantly contained fine 300-700 nm subgrains with a cellular structure. It was concluded that after the selected heat treatment there was a significant reduction in dislocations. An increase in precipitates was observed after heat treatment, from the original amount of approximately 20 nm to 150 nm

Mathematical model of thermal aggregates

Tepelné agregáty môme charakterizova jako priemyselné pece s ve¾kou spotrebou energie. Jednou z moných ciest zníenia spotreby energie je optimalizácia a priebené riadenie priemyselných tepelných agregátov pomocou simulaèných modelov. Východiskom pre tvorbu simulaèných modelov je matematický model. Matematické modelovanie tepelných procesov je zaloené na rieení parciálnych diferenciálnych rovníc a nelineárnych algebraických rovníc popisujúcich základné procesy prenosu tepelnej energie. V príspevku je popísaná základná metodika tvorby matematického modelu zónovou metódou vrátane efektívneho rieenia. Prínosom príspevku je rozpracovanie analytického postupu rieenia nelineárneho systému bilanèných rovníc, ktorého pouitie znaène urých¾uje priebeh simulácie v porovnaní s numerickým rieením

PBCAVE: Program for exact classification of the mesh points of a protein with possible internal cavities and its application to Poisson–Boltzmann equation solution

The main contribution of the program is in the analytic approach to thesetting of dielectric constant for all discretization points of a grid in the computationaldomain according to their locations with respect to the molecularsurface allowing also taking into account possible cavities. Assigned valuesof dielectric constant are used in a solver of the linear Poisson-Boltzmannequation for a protein–water system using a finite difference method

The mechanical properties of OFHC copper and CuCrZr alloys after asymmetric rolling at ambient and cryogenic temperatures

This work deals with comparing the mechanical properties of OFHC copper and CuCrZr alloys processed by asymmetric ambient rolling (ASaR) and asymmetric cryorolling (AScR). The conditions for asymmetrical rolling were ensured by different diameters of the main rolls. The thickness of samples was reduced about 20% - 70% at ambient temperature and at a temperature of liquid nitrogen. Mechanical properties such as yield strength, tensile strength, reduction of area and microhardness were determined for all rolled samples. Rolling at cryogenic temperatures provide about 50-60MPa more tensile strength for Cu and 60-80 MPa for CuCrZr alloys when rolling at ambient temperature. After AScR of CuCrZr alloys, a start of precipitation was shifted at the temperature of 434∘C and recrystallization was a part of the precipitation peak. According to the results, plastic deformation through shear bands is the dominant mechanism in materials with lower stacking fault energy (CuCrZr) treated under cryogenic conditions

Evaluation of Powder Metallurgy Workpiece Prepared by Equal Channel Angular Rolling

The aim of the article is to examine the workability of sintered powder material of aluminum alloy (Alumix 321) through severe plastic deformations under the conditions of the equal channel angular rolling (ECAR) process. Accordingly, the stress–strain analysis of the ECAR was carried out through a computer simulation using the finite element method (FEM) by Deform 3D software. Additionally, the formability of the ALUMIX 321 was investigated using the diametrical compression (DC) test, which was measured and analyzed by digital image correlation and finite element simulation. The relationship between failure mode and stress state in the ECAR process and the DC test was quantified using stress triaxiality and Lode angle parameter. It is concluded that the sintered powder material during the ECAR processing failure by a shearing fracture because in the fracture location the stress conditions were close to the pure shear (η and θ¯ ≈ 0). Moreover, the DC test revealed the potential role as the method of calibration of the fracture locus for stress conditions between the pure shear and the axial symmetry compression