Experimental – Numerical Analysis of Stress State in Front of the Crack Tip of Modified and Unmodified G17CrMo5-5 Cast Steel by Rare Earth Metals in a Brittle-Ductile Transition Region

Abstract

In the paper presented experimental data and numerical analysis of stress distribution in front of the crack of two melts of low-alloy G17CrMo5-5 cast steel-modified (M) by rare earth metals and original, unmodified (UM) in the temperature range, according to the brittle-ductile transition region. Experimental tests include determination of the tensile properties and fracture toughness characteristics for the UM and M cast steel. Numerical analysis includes determination of stress distribution in front of the crack at the initial moment of the crack extension. In the numerical computations, experimentally tested specimens SEN(B) were modeled. The true stress-strain curves for the UM and M cast steel were used in the calculation. It was shown that the maximum of the opening stresses at the initial moment of the crack extension occurs in the axis of the specimens and reaches similar level of about 3.5σ 0 for both UM and M cast steel. However, the length of the critical distance, measured for stress level equal 3σ 0 , is great for the M in comparison to the UM cast steel. Also was shown that the UM cast steel increased the level of the stress state triaxiality parameters that resulted in a decrease of fracture toughness.Keywords: fracture toughness in a brittle-to-ductile transition region, stress distributions in front of the crack, cast steel, modification by rare earth metals

Exploratory Data Analysis for the Evaluation of Tribological Properties of Wear-Resistant Surface Layers Modified with Rare-Earth Metals

“…By influencing changes in the microstructure of steel, alloys, and metallic layers, REM directly improve tribological properties, corrosion resistance, mechanical properties, and resistance to oxidation [ 9 , 10 , 11 ]. Rare Earth metal additions change the parameters of the structure, e.g., grain size, number and size of inclusions [ 12 , 13 , 14 , 15 ], and the mechanical. Adding La 2 O 3 , Gd 2 O 3 , Lu 2 O 3 particles increases the hardness of surface layers [ 16 , 17 ].…”

Research Progress on the Ductile-to-Brittle Transition of Metal Materials: The Impact of FATT50

“…(1) 关键词主要集中在材料的力学性能方面，如 Brittle-Ductile Transition [7-13]、Mechanical Properties [14][15][16][17][18] 、 Deformation [19][20][21][22][23][24] 、 Fracture [25][26][27][28][29][30] 、 Toughness [31][32][33][34]、Strength [33,[35][36][37][38][39]、Brittle [40][41][42][43][44][45]、 Plasticity [46][47][48][49][50][51] [110,111]。 磷元素是也钢中一种常见的微量元素，其含量一 般在 0.005%~0.04%之间 [112,113] [122,125,126] [13] Murray G T. Brittle-Ductile Transition Temperatures in Ionic Crystals [J]. Journal of the American Ceramic Society, 1960, 43(6): 330-334.…”