The effect of smelting and processing technology of 30 t EAF-LF-VD-Φ200 mm electrode-Φ360 mm ESR ingot- 120 mm×120 mm forging billet-Φ50 mm rolled bar on the eutectic carbide in stainless bearing steel 9Cr18 is analyzed by  optical microscope.Tested results show that,reduce the molded electrode pouring temperature from 1500- 1510 ℃ to 1485- 1495 ℃,reduce the ESR melting speed from4.5 kg/min to3.5kg/min,strengthen the electroslag remelting cooling conditions can effectively reduce the eutectic carbide in the original form in process of smelting; and the large carbide particles can be broken,the particle size can be reduced,and the degree of carbide band and network aggregation can be reduced by the way of forging penetration and large deformation to effectively improve the eutectic carbide rating of stainless bearing steel and reduce the carbide particle size.

In accordance with the current in electroslag remelting(ESR)GCr15 bearing steel D inclusions exceeding the standard problem,the different slag systems are designed,and respectively with the help of Factsage software and empirical formulae to calculate the melting characteristics of the slag system,viscosity,electrical conductivity and other physical parameters,using laboratory slag metal balance experiments and field 2.5 t electroslag remelting experiments,the results show that, the optimal ESR slag system is 55CaF ₂-25Al ₂O ₃- 15CaO-5MgO.With use of the optimal slag system the average total oxygen content in steel is 41.98% lower than that with the traditional slag system,and can reduce the change in the total oxygen content of steel in different locations of electroslag ingot; as compared to the original slag system the number of 1-5  μm inclusions  decreases by 31.25%.Through the slag system on inclusions control,it can improve class D inclusion in GCr15 bearing steel,rating level reaches 0.5,and can better“clean”electric slag ingot.

17-7PH precipitation hardening stainless steel consumable electrode is prepared by 35 t electric arc furnace- AOD decarbonization- LF refining- ingot casting process, and 2 t electroslag ingot is obtained by gas shielded electroslag furnace. The change law of inclusion number, size and composition in 17-7PH steel before and after electroslag remelting are analyzed by ASPEX scanning electron microscope, and the morphology and type of inclusions in steel is further observed by SEM-EDS. The experimental results show that, after electroslag remelting, the oxygen content decreases from 6.6 x 10 ^-6 to 5.7 x 10 ^-6 and the nitrogen content decreases from 200 x 10 ^-6 to 180 x 10 ^-6. The types of inclusions don't change before and after remelting, but the total number of inclusions decreases significantly, especially the number and size of large particle inclusions decrease significantly. The total inclusions in electroslag ingot are mainly AIN inclusions, which are large in size and most in quantity. In order to improve the cleanliness of 17-7PH steel electroslag ingot , it is necessary to reduce the nitrogen content of consumable electrode as much as possible, so as to reduce the formation of AIN inclusions formed during electroslag remelting.

The research and application achievements of die casting steel materials in China are introduced.By studying the influence of alloying elements on material properties of die material, a new die casting die steel with low Si, V and Ni, CO and W has been developed. By reducing the content of S in steel, using RE to change the shape of inclusion and optimizing forging process, the isotropic properties of the die-steel can reach more than 90%；To make a comparison between conventional electric slag, gas shielded electric slag and vacuum consumable  process remelted three die-casting material,  nitrogen in steel is respectively  150×10 ^-6,90 ×10^-6 and 40×10 ^-6, oxygen content in steel is respectively 24×10 ^-6, 15×10 ^-6 and 6×10 ^-6; By ASPEX Explorer metal quality analyzer inclusions index statistics and analysis of three kinds of technology, using vacuum consumable smelting exponential decline in non-metallic inclusions, non-metallic inclusions and no larger than 5 um, material impact performance boost, 7 mm × 10 mm gap impact energy can reach 450 J；To develop high-end die-casting mould material microstructure, the non-notched impact evaluation index standard and specification are established with the development of integrated die casting technology, the future mold material shall develop toward large-scale, super pure, high precision and long life direction.

By using combination teachnology of 20 t EAF-LF-VD, 20 t argon protection ESR unit remelting, 1 250 ~1 280 ℃ high temperature homogenization treatment, 60 MN oil pressure quick forging machine multiple forging and 1 000 〜1 050 ℃ high temperature solution treatment process, the inclusion(≤0.5 rating) , structure and lateral impact energy (KV2 25 〜31 J) of produced 640 mm x 1 100 mm 4Cr5Mo2V heavy die steel are higher than the requirement in standard NADCA#207-2018 for advanced steel leave,and the isotropy of steel reaches 0.95.

The tested bearing steel 9Cr18Mo (/% ： 0.98C, 0.21 Si, 0.32Mn, 0.005P, ＜0. 001S, 16.95Cr, 0.51Mo) is melted by 500 kg vacuum induction melting furnace (VIM) -electroslag remelting unit (ESR) -vacuum arc remelting unit (VAR) triplex process, forged breakdown and rolled to Φ30 mm bar products. The gas content, deleterious elements content and non-metallic inclusions in steel 9Crl8Mo are examined and analyzed. Results show that the triplex process is available to increase the cleanliness of bearing steel, the oxygen content in tested steel 9Cr18Mo is 0.0008% , nitrogen content is 0.0038% and the S content is ＜0. 001 % , and with controlling the Ti content and pentad-deleterious elements content in raw materials, in finished products the Ti content is ＜0.002% , the Sn, As and Sb content are respectively ＜0.002% and the Pb and Bi content are respectively ＜0.0001 % ； by triplex process the nonmetallic inclusions in steel is a little, and the inclusions with size less than 3μm amount are more than 90% of total inclusions up to quite high cleanliness level.Material Index Bearing Steel 9Cr18Mo, Cleanliness, VIM-KSR-VAR Triplex Melting Process, Inclusions.

The tested steel 0. 05C-14Mn-19Cr-0. 7N is melted by 1 t non vacuum induction furnace and remelted to ESR ingot. By sampling at center of ESR ingot and using Gleeble 3800 thermo-simulation testing machine the thenno tensile examination of tested steel at 800 ~ 1250 °C with strain rate 0. 005 ~ 10 s^-1 has been carried out to get the effect of temper ature and strain rate on reduction of area of tested steel, and the structure of steel tensile-tested at each temperature is ob served. Examination results show that with temperature increasing from 800 ℃ to 1 250 ℃ the tensile strength of tested steel decreases from 327 MPa to 68 MPa and the reduction of area of steel increases from 22% to 55% ；at 1200℃, with strain rate increasing from 0. 01 s^-1 to 10 s-1 the tensile strength of tested steel increases from 43 MPa to 109 MPa and the reduction of area of steel increases from 38% to 71%. Integrating the experimental results it is obtained that the optimized deformation parameters for high nitrogen austenite stainless steel 0. 05C-14Mn-19Cr-0.7N are rolling at 1200 ~ 1250°C with stain rate 1 ~ 10s^-1.

The 12Cr2Mol VR steel plate production flow is 100 t EAF-LF-VOD-CC-ESR-rolling process. In the electroslag remelting process, the processes such as melting rate reduced by (160 ~ 180) kg/h and nitrogen protection are adopted ； low speed and large reduction rolling process is adopted in the rolling process ； after rolling, 650 ~ 700 °C longtime holding hydrogen diffusion annealing process is adopted. Normalizing at 930 ~ 950 °C ( accelerated cooling) + tempering process at 680 -700 °C are adopted during heat treatment. The surface quality of the produced steel plate is good. The flaw detection level meets the requirements of NB/T 47013. 3-2015 with No. 1 amendment T I rating. The composition and microstructure of the steel plate are uniform. The mechanical properties are stable to meets the technical requirements.

The GH2132 alloy (1.90% ~2. 30%Ti) has the problems of large loss of Ti element ( A[Ti]0. 37% ~ 0. 57% ) in ESR process, the Ti content in steel is only 1. 83% ~ 1. 89% in ESR middle and last period. By adopting (/% ) CaF： Al ₂O ₃： CaO： TiO ₂ =75： 15： 5： 5 slag system to replace original CaF270% + Al ₂O ₂0% slag system, the unstable oxide (SiO ₂ + FeO) in the slag is controlled to be less then 0. 6% , and die controlled melting rate of the smelting process decreases from 6. 1 -6. 3 kg/min to 5. 3 -5. 6 kg/min, etc technological measures, as a result, the Ti content in steel at ESR ingot each part is 2. 06% ~2. 21% , and the Ti burning loss A[Ti] decreases to 0. 19% ~0. 34%, ESR ingots are sampled to check the inclusions after forging, and it is found that the inclusions have also been significantly improved after the process adjustment. The class inclusions of D fine system is controlled below rating 0. 5, which meets the requirements.

Effect of the non-electromagnetic stirring ( non-EMS) and the EMS with 6 Hz and 50 ~ 200 A in 1 t electroslag remelting (ESR) process on solidification structure o£ alloy GH4169 (/% : 0.04C, 0.21 Si, 0.05Mn, 52. 85Ni, 19. 80Cr, 5.20Nb, 3.05Mo, 0.55Al, 1.02Ti) has been studied. Results show that the EMS may obviously fine grains of alloy, increase ratio of equiaxed crystal and decrease spacing between secondary dentritic arms ； but as stirring electric current intensity is >100 A, the eutectic structure in ESR ingot increases to reduce the plasticity of ingot; as the current intensity is 50 A with frequency 6 Hz, the ratio of equiaxed crystal is max and the spacing between secondary dentritic arms is minimum, the Laves phase content in center of ESR ingot is lowest and the alloy with minor eutectic structure to get excellent plasticity of alloy.

The effect factors on intensity of cooling of large-scale ESR furnace mold have been analyzed by using heat transfer theory, it is obtained by calculation that the optimum water flow rate for the 1 800 mm diameter mold is 1. 2 m/s, and the optimum design scheme for high speed water case type mold with case layer thickness 10 mm is put forward. The production results by remelting 60 t 0.030C-17.10Cr-ll.80Ni-2.55Mo-0.072N austenite stainless steel ESR ingot with voltage 77. 5 V, current 19 kA, remelting speed 31. 6 kg/min and water rate 1. 2 m/s show that the formability of ESR ingot is better, and the forming quality of ESR ingot is improved with smooth ingot surface and uniform distribution of slag skim.

The effect of consumable electrode on ESR ingot cleanliness was investigated during electroslag remelting (ESR) of G20CrNi2Mo bearing steel. The results show that the ingot cleanliness is much correlated with that of electrode. The ingot oxygen content presents a rising trend with increasing electrode oxygen content. The SEM-EDS analysis reveals that the number density of low-melting-point CaO-MgO-Al ₂O ₃ inclusions in high oxygen-containing electrode is much larger than that in low oxygen-containing electrode. The low interfacial energy between low-melting-point inclusions and steel significantly limits the efficiency of inclusions removal, thus resulting in relatively high ingot oxygen content. With increasing carbon content before EAF tapping, the number of ingots less than 0.002 0% oxygen occupies total more than 90%.

In order to control structure non-uniformity and carbide segregation of high speed steel ingot, ingots of small size are usually produced by ESR, but its production efficiency is low, the rate of finished product is low. Long electrosiag billets with small specifications for ESR fest Withdrawing can improve production efficiency and finished product rate, we made 160 mm x 160 mm square billet of M2 high speed steel using T-type conductive crystallizer for ESR fast Withdrawing with different melting speed and forged and rolled, through the detection and analysis of the composition, low magnification, cast structure and carbide irregularity of the electroslag billet and the size of large particles of carbide, mean¬while ,it is compared and analyzed with Φ 220 mm ingot rolling for conventional ESR, analysis shows that electroslag billet for ESR fast Withdrawing with 400 kg/h remelting speed has stable composition and good macrostructure, the carbide variability and carbide dimensions of large particles of rolled materials produced are similar to those Φ 220 ingot rolling materials for conventional ESR, and the production efficiency and the rate of finished products have been improved obviously.

It was studied the quality of carbide, non-metallic inclusions and composition change of sulfur bearing M35 high speed steel (0. 015% ~ 0.030 S) using acid slag remelting in atmospheric conditions using the 1 t double electrode furnace. When the acid slag was remelting,the sulfur,silicon,manganese,chromium have a large difference between the two ends of the ingot, the difference reduced using the method of adding calcium sulfide when slag melting and adding manganese iron when Slag dump. The quality level of carbide nonuniformity granularity of sulfur bearing M35 high speed steel mill bar is similar to that of conventional alkaline slag,non-metallic inclusions class A is less than 1.5 ,B, C and D, which are less than or equal to 1.0.

Grade (/% ：0.3C-1.6Si-0. 8Mn-1.1Cr-0.48Mo-0.1 V)of ultra high strength steel has been melted by 6 t vacuum induction & vacuum arc remelting processes. Through comparing the structures and mechanical properties of this steel melt with different superheat degree,the test results show that the rating of banding structure decreases from 2.5 to 1 and the fracture toughness average value increases from 85 MPa . m ^1/2 to 116. 3 MPa . m ^1/2 when VIM casting temperature decreases from (1 600 ± 10) °C to (1 560 ± 10) °C . So the low temperature casting process is the key to improve the uniform of material.

Based on electromagnetic stirring (EMS) in the electroslag process fbr bearing steel GCrl5,the effects of EMS on the superalloy solidification structure and chemical composition are analyzed. The result is as follows: Electromagnetic electroslag can signiHcantly improve the heat transfer condition of ingot solidification process, reduce the formation of network carbide in steel GCrl5 ingot. At the same time, because of the effect of electromagnetic stirring, the segregation index of main elements such as C and Cr in the ingot is stable less than 1.03. When the stirring current is 50 A to 2(X) A, the frequency is 6Hz. , there is no net carbide in the center of the ingot, and the carbon segregation index is 1.02.

The oxygen and nitrogen content of GH3128 alloy with two smelting processes of "VIM + ESR" and "NVIM + ESR" are measured by oxygen nitrogen analyzer, and the thermodynamic calculation of deoxidation and denitrifiation has been carried out. The composition, size distribution and quantity of inclusions in GH3128 alloy with two smelting processes are analyzed by ASPEX SEM . The results show that： The process of M VIM + ESR" can remove the N in the alloy more effectively, the inclusions are mainly Al-Ti-0 composite oxide inclusions, with a small number of Al ₂O ₃ and TiO _x oxide inclusions, the inclusions in alloy by process of "NVIM + ESR" are not only oxide inclusions, but also sulfide and nitride inclusions. And uses the vacuum smelting process can effectively reduce the number of inclusions, and refine the inclusion.

The composite roll is a kind of bimetallic composite material which consists of a high wear-resistance mate¬rial as the working layer and a high strength, toughness material as the core respectively. In this paper, a systematical introduction is given for the preparation of bimetallic composite roll by electroslag metallurgy technology including ESR clad¬ding method, electroslag surfacing by liquid metal and consumable mold cladding method at home and abroad. The influence of consumable electrode form, conductive circuit scheme, supply method of the outer metal and equipment structure on the bimetallic cladding process and the comprehensive performance of composite roll are analyzed. At the same time, the basic process characteristics and control keys technology of the different methods are summarised. Based on the analyses of the development history of electroslag cladding technology and the stability control of composite roll performance, the future prospect and development of the preparation of bimetallic composite roll by electroslag cladding method is prospected.

By analyzing microstructure and inclusions, analyzing chemical composition and mechanical properties of 4J36 alloy (/% ：0. 17 ~0.18C,0. 18 〜0.27Si,0.39 〜0. 40Mn,0.009P, < 0.0005S,35. 8 〜36.ONi) before and after ESR(electro-slag remelting) , the effect of ESR on microstructure and mechanical properties of 4J36 alloy is studied. The results show that after ESR the chemical composition of 4J36 has almost no change, the sizes of gains decrease, and the amount and sizes of inclusions also decrease. Yield strength and tensile strength are improved to a certain extent, elongation increases from original 34% to 58% , and impact energy at - 196℃. increases from original 145 J to 208 J.

The ingredient and phases of solid phase slag without remelting liquid slag air cooling and with liquid-slag reaction remelting slag, air cooling of slag 70% CaF ₂-25% Al ₂O ₃-5% CaO for ESR of electrothermal alloy steel 0Cr21A16NbRE with normal remelting process (A =2800 A,V =30 V) are studied,and the burning loss of RE elements in liquid is analyzed. The results show that without remelting air cooling slag has not RE elements it locates in CaF ₂ -CaO • 2Al ₂O ₃-CaO • 6A1 ₂O ₃ sub-triangle. The solid phase slag with liquid-slag reaction can be divided into five layers with different colors, difierent phase, the content of CaF ₂ on the top is highest and decreases layer by layer, A1 ₂O ₃ increase simultaneously ,RE oxide is found in layers and at the middle and bottom its content is higher, (Ce,La)x( A10 ₂ )  y is major RE oxide phase in slag, which density is high. It is obtained by calculation that slag oxidability is stronger in the middle and bot¬tom of slag,RE element in steel is oxided here. Increasing the Y ₂O ₃ amount in slag is favourable to increase the RE element Y content in ESR ingot.