Brittle Temperature Research Articles

A Study of Microstructure and Mechanical Properties for the Autogenous Single-Pass Butt Weldment of a Ferritic/Martensitic Steel Using Gas Tungsten Arc Welding

A 12% Cr ferritic/martensitic steel, HT-9, has been used as a primary core material for nuclear reactors. The microstructure and mechanical properties of gas tungsten arc butt welded joints of HT-9 in as-welded, and as-tempered conditions have been explored. In as-welded condition, the fusion zone (FZ) contained a fresh martensite matrix with delta (δ)-ferrite. The δ-ferrite was rich in Cr and depleted in C compared with the matrix. The heat-affected zone (HAZ) could be divided into three areas as the distance from the fusion line increased: δ-ferrite/martensite duplex zone, fully recrystallized zone, and partly recrystallized zone. Prior austenitic grains did not coarsen in the δ-ferrite/martensite duplex zone due to the newly nucleated δ-ferrite grains and incompletely ferritizing (δ-ferrite) during the welding thermal cycle. The weldment microhardness distributed heterogeneously with values above 600 HV1.0 in the HAZ and FZ and 250 HV1.0 in the base metal (BM). Solute C in the matrix, induced by the dissolution of carbide during the welding process, dominated the microhardness variation. Low toughness was observed in the FZ with a quasi-cleavage fracture tested from − 80 to 20 °C. The tensile fracture occurred in the relatively soft BM tested from 20 to 600 °C. In as-tempered condition (760 °C for 1 h), M23C6-type carbides precipitated within the martensitic laths, the lath boundaries, and the δ-ferrite/martensite interfaces. Moreover, V, Cr, Mo-rich nitrides with very small size also precipitated in the δ-ferrite/martensite interface. The tempering treatment improved the homogenous distribution of weldment hardness significantly. Tensile fracture still occurred in the BM of the weldment specimens tested from 20 to 600 °C. The impact toughness improved significantly, but the ductile–brittle transaction temperature was − 12 °C which was higher than that of the normalized and tempered (N&T) BM. δ-ferrite was considered to be one of the major factors aggravating the impact toughness in the FZ.

Metal Examination and an Assessment of a Feedwater Pipeline’s Reliability after Prolonged Operation

The operational reliability of feed pipelines made of 15GS steel used at thermal power plants is considered. The reason for the study consists in an incident at a Mongolian TPP, constructed according to a Soviet project, consisting in the detection of cracks in one of the bends of the feed pipeline. The zone of metal damage was removed, after which three fragments of the bend were sent for investigation to the All-Russia Thermal Engineering Institute (JSC VTI). After a nondestructive testing of the bend under laboratory conditions demonstrated the absence of defects in the metal and, thereby, indicated the locality of damage, the metal of the bend was examined in samples. The studies on the chemical composition and microstructure of the bend metal have confirmed its overall compliance with engineering specifications in these characteristics. According to the results of mechanical tests, the strength and plastic properties of the bend metal also met the requirements of engineering specifications. Furthermore, the metal of the stretched zone of the central part of the bend, wherein damage was detected, has exhibited a higher level of strength characteristics and a lower plasticity compared to other sections of the bend. In addition, the metal of this zone exhibited a lower impact strength and an increased value of the ratio between yield strength and tensile strength, which indicates brittle conditions. This has been confirmed by the determination of the critical brittleness temperature, whose value for the metal of the stretched zone of the central bend fragment is rather high amounting to at least 90°С. The results of strength calculations have confirmed compliance with the standard strength conditions for pipeline bends and, at the same time, they have demonstrated a very high level of local tensile stresses on the outer surface of the stretched bend zone. The calculation of the tendency of bends for the brittle fracture has shown that, taking into account the dimensions of surface’s technological defects allowed by the engineering specifications, the boundary of the brittle fracture of the bend is significantly lower than the pipeline operation temperature, but the hydraulic testing of the pipeline should be carried out at a temperature not lower than 60°C according to the conditions of brittle strength.

Influence of Charge Quality on Physical, Mechanical and Operational Properties of Low-Alloy Steel 30KHGSA

Purpose of reseach is to study the influence of the quality of the original charge on the complex of physical, mechanical and operational properties of structural low-alloy steel 30HGSA.Methods. As an object of research, a typical representative of low-alloy structural steels has been chosen - steel 30HGSA, smelted using metallized sponge iron pellets, ordinary scrap metal and billets obtained by the method of a boiling slag layer. In accordance with the set objectives of the study, steel 30HGSA of various melts, obtained with different charge, had the same conditions for melting, evacuation, deoxidation, casting and crystallization. The casting temperature was 1600...1620 оC and the post-vacuum treatment temperature was 1530...1560 °C. Duration of evacuation - 5 minutes. Casting of melts was carried out into cast iron molds with a siphon for 4 ... 5 minutes. Deoxidation was carried out in a ladle with aluminum in the amount of 4 ... 4.5 kg / melt. After solidification, the ingots were cooled in special wells. The ingots were cut into 3 parts: head, middle and bottom (600 × 600 mm). The middle part was then hot forged and rolled to a Ø30 mm bar. The length of the rod was 2 ... 3.4 m. After hot deformation, the rods were cooled in air.Results. Mechanical tests have been carried out. Statistical processing of experimental results has been performed. Regularities of changes in the characteristics of mechanical properties have been revealed: tensile strength, creep strength, relative narrowing of the cross-sectional area of the sample, relative elongation of the initial working length, impact strength (σВ, σ0.2, ψ, δ, aН).Conclusion. It has been found that with an increase in temperature, the mechanical properties of steel 30HGSA, smelted on various charges, decrease. It has been established that the cold brittleness threshold of 30HGSA steel is lower for purer melts on spongy iron and intermediate product KShS, the value of impact toughness at low temperatures is higher than in melting on a conventional metallized charge. Noticeable softening begins at a tempering temperature of 300 °C The temperature of the maximum tempering brittleness for steel 30HGSA, melted on a conventional metallized charge, is 550 °C It is shown that steel 30HGSA smelted with a pure original charge (spongy iron) has a lower tendency to temper brittleness than steel smelted with a conventional charge. The value of the impact toughness of the steel of this melt is higher than that of the steel of conventional melting over the entire tempering temperature range.

Use of wood processing industry waste for bitumen modification

The paper provides information about the method of obtaining a modifying additive to bitumen, including wood filler. The pore space of the filler contains a basalt reinforcing filler with an average particle size of 150-300 nm. Scots pine bark with an average particle size of 0.5-1 mm was used as a wood filler. The modifying additive was obtained by mixing fine basalt (30 % by weight) and wood bark. After careful mixing for 5 minutes, water was added, the mass of which is twice more than the calculated mass of the reinforced bark. Then the mixture was homogenized. The use of an additive for the preparation of a bituminous binder improves the thermal and physical characteristics of the organic binder (softening temperature and brittleness temperature). In comparison with other traditional stabilizing additives, the use of the proposed composition for the preparation of a bituminous binder also improves the thermal and physical characteristics of the organic binder, such as the brittleness temperature. A decrease in the brittleness temperature of the mixture indicates an increase in the frost resistance of the modified organic binder. For other characteristics, the modifying additive has a comparable effect on the properties of the binder with traditionally used materials.

ДО ПИТАННЯ ТОЧНОСТІ ВИЗНАЧЕННЯ КОЕФІЦІЄНТА РАДІАЦІЙНОГО ОКРИХЧУВАННЯ

The paper presents the statistical analysis of experimental results of radiation-induced critical brittle temperature ΔTF shifts and reference temperatures ΔT0 obtained respectively from the impact bend and fracture toughness tests of the reactor vessel metal surveillance specimens to define the possibility of their mutual application for the irradiation embrittlement coefficient to be determined more accurately. The correlation between these parameters is shown to remain up to the accumulation of over-design fast neutron fluence.

High‐Temperature Tensile Properties and Deformation Behavior of Three As‐Cast High‐Manganese Steels

Herein, the high‐temperature tensile properties and deformation behavior of three as‐cast high‐manganese steels with various carbon contents (0.028, 0.28, and 0.64 wt%) are investigated using a combination of hot tensile tests and isothermal hot compression on a Gleeble‐3500 thermomechanical simulator with different temperatures and strain rates. The results indicate that the carbon content increase makes a greater number of Mn–C dipoles available for a short‐range ordering and increases in the peak stress and the maximum flow stress at a constant test temperature and strain rate. In contrast, the stress decreases with increasing test temperatures. The change in carbon content affects the phase transformation at high temperatures, leading to differences in hot ductility. Steels with a carbon content of 0.028 and 0.28 wt% have similar hot brittle temperature ranges, whereas the ductility of the steel improves with increasing temperatures when the carbon content increases to 0.64 wt%. For the hot compression test, the influence of strain rates in increasing the maximum stress grows with increasing carbon content. The hot deformation activation energies of different steels are confirmed, with which the peak stresses could be predicted by the Z parameter in the hyperbolic sine equation. A good correlation is obtained between model predictions and experimental observations in the peak stress.

Stereocomplexed Poly(lactide) Composites toward Engineering Plastics with Superior Toughness, Heat Resistance and Anti-hydrolysis

Poly(lactide), PLA, suffers from brittleness and low heat deflection temperature (HDT), which limits its application as an engineering plastic. In this work, poly(L-lactide)/poly(D-lactide)/ethylene-vinyl acetate-glycidyl methacrylate random copolymer (PLLA/PDLA/EVM-GMA = 1/1/x) composites were prepared by melt blending, and the in situ formed EVM-g-PLA copolymers improved the compatibility between PLA and EVM-GMA. Subsequently, the blends were subjected to a two-step annealing process during compression molding, i.e. first annealing at 120 °C to rapidly form a certain amount of stereocomplex (sc) crystallites as nucleation sites, and then annealing at 200 °C to guide the formation of new sc crystallites. Both differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD) measurements confirmed the formation of highly stereocomplexed PLA products. Mechanical results showed that the PLLA/PDLA blend with 20 wt% of EVM-GMA had a notched impact strength up to 65 kJ/m2 and an elongation at break of 48%, while maintaining a tensile strength of 40 MPa. Meanwhile, dynamic mechanical analysis (DMA) and heat deflection tests showed that the PLA composite had an HDT up to 142 °C which is 90 °C higher than that of normal PLA products. Scanning electron microscopy (SEM) confirmed the fine dispersion of EVM-GMA particles, which facilitated to understand the toughening mechanism. Furthermore, the highly stereocomplexed PLA composites simultaneously exhibited excellent chemical and hydrolysis resistance. Therefore, these fascinating properties may extend the application range of sc-PLA material as an engineering bioplastic.

Bitumen chemical modification by a thermoplastic polymer

Oil road bitumen was modified by a copolymer of ethylene with vinyl acetate (EVA) and 3-glycidyloxypropyltrimethoxysilane (epoxysilane). These modifiers were simultaneously introduced into the BND 90/130 oil bitumen at a temperature of 165 °C. The components were mixed up during two hours with further isothermal holding at the same temperature during the required period. Epoxysilane crosslinks bitumen with EVA making it possible to obtain an immiscible bitumen polymer binder. The optimal content of EVA is 12 mph, epoxysilane -3 mph with a mixing time of 4 hours. The optimal bitumen polymer binder is characterized by the following properties: softening point of 66 °C, penetration at 25 °C = 50, penetration index of 2.15, brittleness temperature of -22 ° C. Separation is significantly reduced. NMR spectroscopy has revealed that the introduction of the binding agent to the bitumen-polymer binder does not create low-mobile structures. It allows forecasting the high binder stability during storage and transportation.

Solidification Cracking Assessment of LTT Filler Materials by Means of Varestraint Testing and µCT.

Investigations of the weldability of metals often deal with hot cracking, as one of the most dreaded imperfections during weld fabrication. The hot cracking investigations presented in this paper were carried out as part of a study on the development of low transformation temperature (LTT) weld filler materials. These alloys allow to mitigate tensile residual stresses that usually arise during welding using conventional weld filler materials. By this means, higher fatigue strength and higher lifetimes of the weld can be achieved. However, LTT weld filler materials are for example, high-alloyed Cr/Ni steels that are susceptible to the formation of hot cracks. To assess hot cracking, we applied the standardized modified varestraint transvarestraint hot cracking test (MVT), which is well appropriate to evaluate different base or filler materials with regard to their hot cracking susceptibility. In order to consider the complete material volume for the assessment of hot cracking, we additionally applied microfocus X-ray computer tomography (µCT). It is shown that by a suitable selection of welding and MVT parameter the analysis of the complete 3D hot crack network can provide additional information with regard to the hot cracking model following Prokhorov. It is now possible to determine easy accessible substitute values (e.g., maximum crack depth) for the extent of the Brittleness Temperature Range (BTR) and the minimum critical strain .

Effect of Cladding Conditions on Solidification Cracking Behavior during Dissimilar Cladding of Inconel Alloy FM 52 and 308L Stainless Steel to Carbon Steel: Evaluation of Solidification Brittle Temperature Range by Transverse−Varestraint Test

In this study, solidification cracking behavior and susceptibility in dissimilar cladding of Inconel alloy FM 52, 308L stainless steel to carbon steel, was investigated by submerged arc welding and transverse−Varestraint testing with gas tungsten arc welding. The effect of cladding conditions on cracking behavior and susceptibility was extensively evaluated, and metallurgical factors affecting susceptibility were clarified. Depending on the cladding sequence (cladding combination A: Inconel 52→308L, cladding combination B: 308L→Inconel 52), opposite types of solidification cracking behavior were observed. Specifically, solidification cracking was observed only for cladding combination A. Using transverse−Varestraint tests, the solidification brittle temperature range (BTR) was determined to be 298 K for cladding combination A and 200 K for cladding combination B. The reason for solidification cracking in cladding combination A could be its higher solidification susceptibility (i.e., a larger BTR (298 K)) compared with cladding combination B (BTR: 200 K). To elucidate differences in solidification cracking susceptibility, a numerical simulation of non−equilibrium solidification segregation for impurity elements (P, S) was performed, based on velocity dependent solidification theories and the finite differential method. Different segregation behaviors were calculated upon the cladding combinations. The severe segregation of P and S during solidification was found to be one of the important metallurgical factors for the large BTR of cladding combination A, compared with cladding combination B.

Analysis of ductile fractures at the surface of continuous casting steel during hot-core heavy reduction rolling

Abstract Hot-core heavy reduction rolling (HHR2) is an innovative thermomechanical technology whereby steel castings are directly rolled and heavily reduced at the solidification endpoint. HHR2 can effectively eliminate shrinkage porosities without the risk of internal cracking, as the centre deformation temperature has avoided the solidification brittleness temperature range. However, the risk of surface cracks is especially concerning because the lower surface temperature is associated with increased brittleness as compared to the centre. In this study, the EH47 was selected as the research material, which was a crack-sensitive steel with microalloy element Nb. Finite element model (FEM) analysis was used to predict surface ductile fracturing during HHR2. Hot compression tests were performed on specially designed specimens to develop the ductile fracture criterion for the FEM simulation. Pilot plant trials of HHR2 were carried out to verify the accuracy of the FEM calculations. The FEM results revealed that the centreline of a steel casting lateral face was the position where a fracture was most likely to take place. Moreover, the cracking risk itself rises with an increase in the reduction ratio, and the critical reduction ratio was about 59 %. The investigation also revealed that the cracking risk reduced with an increase in the work roll diameter.

Improvement of the cold resistance of the 09G2S steel by programmed hardening combined with additional medium-temperature tempering

The article discusses a method of improving the cold resistance of steels of a ferrite-pearlite class. It has been established that the process of programmed hardening, combined with an additional medium temperature tempering, has a positive effect on the cold resistance of thermally improved 09G2S steel. The mechanical properties of steel grade 09G2S were determined before and after additional tempering at mediumtemperature. It is shown that the new technology allows the critical temperature of brittleness, determined by the criterion of the energy intensity of failure, to be shifted to lower temperatures by 15°C, and at the same time to increase the impact strength of 09G2S steel three times more at a temperature of minus 90°C without changing its strength properties.

Use of Programmed Hardening During Tempering in Order to Improve Steel Brittle Fracture Resistance

A new method for improving ferritic-pearlitic steel brittle fracture resistance is considered. The favorable effect of thermal improvement and subsequent programmed strengthening hardening during additional medium-temperature tempering is demonstrated on the example of steel 09G2S. The new technology makes it possible to lower the steel 09G2S critical brittleness temperature Tc0 determined in terms of the criterion of fracture energy intensity by 20°C, and to increase steel impact strength at –90°C by about a factor of three with retention of the specified strength properties.

Impact fracture energy of steel welded connections in fire and post-fire

Charpy impact tests were conducted on steel welded connections at elevated temperatures and at the ambient temperature after heating and cooling processes. The elevated temperature tests were conducted to examine the Charpy impact energies under the blue brittleness temperature (100–300 °C) of steel. V-notch specimens quarried from steel base metal, weld metal, and heat-affected zone of the welded connection were heated and subjected to Charpy impact tests. In the ambient temperature tests after the heating and cooling processes, the heated specimens were either air cooled in a furnace or quenched with water. The test results show that the Charpy impact energies do not decrease in the blue brittleness temperature, and the quenched welded connections demonstrated very low Charpy impact energies.

A Novel Acetylene-Functional/Silicon-Containing Benzoxazine Resin: Preparation, Curing Kinetics and Thermal Properties.

Benzoxazine resin has been paid more attention in the fields of aviation, electronics, automobiles and new energy industries because of its excellent comprehensive performance. Further application is limited, however, by shortcomings such as high brittleness and high curing temperature. Furthermore, higher thermal stability is imperiously demanded in special areas. Incorporating both an acetylene group and silicon into the benzoxazine monomer is a promising possible solution to improve the curing processability, thermal properties and toughness of benzoxazine. In this paper, an acetylene-functional/silicon-containing benzoxazine monomer was prepared by two-step synthesis, and acetylene-functional benzoxazine was also prepared as a comparison. FTIR and 1H NMR confirmed the molecular structure of acetylene-functional/silicon-containing benzoxazine. Differential scanning calorimetry (DSC) analysis showed that the initial and peak degradation temperatures of acetylene-functional/silicon-containing benzoxazine were decreased by 21 °C and 18 °C compared with acetylene-functional benzoxazine, respectively. The apparent activation energy of the curing reaction of acetylene-functional/silicon-containing benzoxazine was 83.1 kJ/mol, which was slightly lower than acetylene-functional benzoxazine (84.7 kJ/mol). TGA results showed that the acetylene-functional/silicon-containing benzoxazine had a higher thermal stability than acetylene-functional benzoxazine. The temperatures of 5% weight loss of acetylene-functional/silicon-containing benzoxazine were 380 °C in nitrogen and 485 °C in air, and the char yield at 1000 °C was 80% in nitrogen and 21% in air, respectively. The results of mechanical properties showed that the impact strength of acetylene-functional/silicon-containing benzoxazine was higher than acetylene-functional benzoxazine by 35.4%. The tensile and flexural strengths of acetylene-functional/silicon-containing benzoxazine were slightly higher than that of acetylene-functional benzoxazine.

Enhancement of Thermal Stability and Bending Ductility of Fe–Si–B Amorphous Ribbons with Minor Y Addition

The influences of minor Y addition on the thermal stability, crystallization behavior, magnetic property and bending ductility of Fe–Si–B amorphous ribbons have been systematically investigated. The results show that all the ribbons with Y addition are fully amorphous structure, and the introduction of Y can enhance the glass forming ability of Fe–Si–B amorphous alloy. With Y addition, crystallization temperature of the first and second phase shift to high temperature side, the temperature interval between the two crystallization peaks are enlarged, the third phase transitions process of Fe–Si–B amorphous alloy with Y addition corresponds to the precipitation of Fe3B phase. The activation energy of the first and second phase calculated by Kissinger’s formula increased with Y addition. Appropriate Y addition is beneficial for Ms. The measured coercivity Hc gradually decreased with the Y addition increased. The amorphous alloys exhibit good bending ductility in the quenched state. The ductile to brittle temperature increase to 300 °C with 1 at% Y addition. Furthermore, the mechanism of ductile to brittle for amorphous alloy was discussed.

Hot cracking in autogenous welding of 6061-T6 aluminum alloy by rectangular pulsed Nd:YAG laser beam

Due to high hot crack susceptibility of Al-Mg-Si alloys, autogenous welding by rectangular pulsed laser beam has not been generally successful in the removal of cracks. In this research, the effect of pulsed Nd:YAG laser parameters and preheating on the creation of hot cracks in the 6061-T6 aluminum alloy was investigated. The sample that was fabricated by the laser parameters including 1 Hz, 0.12 mm/s, 10 ms, and without preheating exhibited the highest cooling rate and the smallest dendrite arm spacing but no hot crack was observed. The tensile test specimens of this sample fractured at a point far from the weld metal and a decrease in the precipitation of silicon and magnesium in the inter-dendritic space and the reduction of thermal stresses resulted in the elimination of hot cracks. However, according to macro-scale models for the creation of hot cracks, preheating decreased the tensile stresses in the BTR (brittle temperature range), but increasing the preheating temperature led to increasing rather than decreasing the hot crack length. In this case, the formation of hydrogen porosity, the segregation of silicon and magnesium, and the creation of low melting point compounds were the important parameters affecting the hot crack initiation and growth.

Characteristics of the resistance to brittle fracture of the elements of light steel thin-walled structures determined on samples with a sharp notch groove

The structure and mechanical properties of 350 steel (GOST R 52246) are studied under tensile and impact bending in the zones of bend of galvanized light-gage steel structure elements. Batch sheet samples consisting of two and three samples with a V-shaped notch were used for profiles 1.5 and 2.0 mm thick, respectively. It is shown that a visco-brittle transition occurs in the temperature range of 20 – 90°C in galvanized samples subjected to plastic deformation. The critical temperature of brittleness T 34 of steel 350 decreases with a decrease in the thickness of rolled products from 3.0 to 1.5 mm due to a decrease in the rigidity of the stress-strain state under tension. At the same time, the size of ferrite grains in the studied ferrite-pearlite steels (1.17 – 0.22 C; 0.11 – 0.14 Si; 0.49 – 0.54 wt.% Mn) changes slightly and amounts to 8.0 – 8.9 μ m. A crystalline fracture surface oriented perpendicular to the axis of the sample is formed in the zones of bending of 3-mm light-gage steel structure elements in the region of the critical temperature of brittleness in the central zones of the fracture. In the samples 2 and 1.5 mm thick, the fracture surface is formed by two shear planes oriented at an angle of 45° to the sample axis at the base of which the colonies of facets of trans-crystallite cleavage are located. Galvanized steel 350 profiles (GOST R 52246) with a ferrite grain size 8.8 – 8.9 μ m can be used in light steel thin-walled (1.5 – 3.0 mm) structures in the operation temperature range of up to – 65°C.

Improvement of production technology of asphalt concrete with the use of polymer waste

In this study the ROB 70/100 oil asphalt from the Aktau Bitumen Factory «CaspiBitum» was considered. Asphalt was modified with polymer waste to upgrade operating properties. The I-40 industrial oil was used as a softener. Indicators like penetration, extensibility (ductility), brittleness temperature and softening temperature of bitumen were explored in this study. It was shown, that physical-mechanical properties of bitumen increased after modification: needle penetration depth decreased, extensibility decreased, softening temperature increased. In addition, the influence of polymers on the structure of bitumen and the effect of their action in the composition were examined. Structure of polymer waste in Republic of Kazakhstan was analyzed. It was proved, that the usage of the recycled polyethylene as a modifier is a rational approach, and it makes it possible to recycle stocks of secondary polymeric materials. Also problems of improving the properties of polymer-bitumen binder and ecology solved.

Effect of MC carbide formation on weld solidification cracking susceptibility of austenitic stainless steel

The effect of secondary phase formation such as MC carbide during welding on solidification cracking susceptibility of fully austenitic stainless steels with various amounts of alloying elements and carbon was investigated. The solidification cracking susceptibility of Fe-24mass%Cr-26mass%Ni stainless steels with various amounts of niobium, titanium, zirconium, and carbon was evaluated by the Trans-Varestraint test.The addition of alloying elements such as niobium, titanium, and zirconium increased the brittle temperature range (BTR). The BTRs depend on the type and combination of the alloying elements and carbon content. Titanium was the most influential element on the increase in BTR compared to the other elements. The increase in carbon content tended to decrease the BTR, especially for the specimen containing titanium. The alloying elements formed phases such as the film-like MC-type carbide (MC) phase and granular Laves phase in the specimens containing 0.05% C, and a lot of the acicular MC phases in the specimens containing 0.20% C. The start temperature of the secondary phase formation differed depending on the type of the alloying element, and the temperature tended to increase with increasing carbon content. When the additions of niobium and titanium were compared, the amount of titanium segregation during solidification was smaller due to the formation of MC phases. Solidification simulation revealed that a higher amount and faster formation of the MC phase during solidification in 2Ti–20C contributed to reducing the BTR by increasing the carbon content. Thus, it is considered that the weld solidification cracking susceptibility depended on the type and amount of formation morphology, as well as start temperature during solidification corresponding to the composition of alloying elements and carbon.