scholarly journals Mastering of production of lead-free ecologically clean free-machining steels

2019 ◽  
Vol 75 (3) ◽  
pp. 337-343
Author(s):  
A. V. Ryabov
Keyword(s):  
Steel Industry ◽  
Lead Free ◽  
Observation System ◽  
Ecological Studies ◽  
Corrosion Resistant ◽  
X Ray ◽  
Metallic Inclusions ◽  
Steel Alloying ◽  
Austenitic Grain Size ◽  
Nickel Tungsten

Both in the domestic and world steel industry alternative ecologically clean free-cutting steels, having cutting machinability characteristics and mechanicalproperties, comparable with lead-containing steels, but voided of their drawbacks,are actively searched. First ofall the alternative steels should not be not so ecologically harmful. Scientific and technological aspects of lead-free free-machining steels production, alloyed by bismuth, calcium, tin, boron and nitrogen presented. Solubility of bismuth in iron and iron alloys with chromium, manganese, nickel, tungsten, vanadium, cobalt,phosphor, sulphur, aluminum, carbon and other elements at the temperature of 1550–1650 ºСdetermined. Parameters of interaction of the first and second order calculated. Study of bismuth behavior and tin spherical samples in 40X steel melt accomplished. The study done at the high temperature facility with controlled atmosphere and X-ray TV observation system. Simulation of phase compositions multicomponent alloys of steel АВЦ40ХГНМaccomplished by application of a program package FactSage. Within the study,a production technology of lead-free, ecologically clean free-machining, steels elaborated and masteredat OJSC “Zlatoust electro-metallurgical works”. Free-machining corrosion-resistant steels (АВЦ19ХГН,  АВЦ40Х,  АВЦ40ХГНМ,  АВЦ12Х18Н10, АВЦ40Х13, АВЦ14Х17Н2) alloyed by bismuth and calcium, steels (АО40Х, АО30ХМ) alloyed by tin, and steels (А38ХГМАРand А30ХМАР) containing BN were the objects of the study. The steels samples were in the form of forged billet of 10, 20 and 80 mm diameter and ingots of 18 and 500 kg (round 345 mm). Steel quality characteristics determined such as mechanicalproperties in longitudinal and cross directions of ingots, uniformity of distribution of fusible elements, carbon and Sulphur along the axis zone and in billet transverse sections. Pictures of ingots macrostructure by height and section obtained. Estimation of hardenability and steel contamination by non-metallic inclusions, austenitic grain size, steel machinability by cutting, surfacequality of re-worked billet and steel macrostructure accomplished. Comparable ecological studies of atmosphere contamination during the steel alloying also accomplished.

scholarly journals Lead-free halide perovskite Cs3Bi2Br9 single crystals for high-performance X-ray detection

2021 ◽  
Author(s):  
Xiang Li ◽  
Xinyuan Du ◽  
Peng Zhang ◽  
Yunqiu Hua ◽  
Lin Liu ◽  
...  
Keyword(s):  
Single Crystals ◽  
High Performance ◽  
Lead Free ◽  
X Ray ◽  
Halide Perovskite

High-Stability Flexible X-ray Detectors Based on Lead-Free Halide Perovskite Cs2TeI6 Films

2021 ◽  
Author(s):  
Jun Guo ◽  
Yadong Xu ◽  
Wenhui Yang ◽  
Bao Xiao ◽  
Qihao Sun ◽  
...  
Keyword(s):  
High Stability ◽  
Lead Free ◽  
X Ray ◽  
Halide Perovskite

scholarly journals Tailoring the electron and hole dimensionality to achieve efficient and stable metal halide perovskite scintillators

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Zhifang Tan ◽  
Jincong Pang ◽  
Guangda Niu ◽  
Jun-Hui Yuan ◽  
Kan-Hao Xue ◽  
...  
Keyword(s):  
Water Solubility ◽  
Radiation Stability ◽  
Metal Halide ◽  
Lead Free ◽  
X Ray ◽  
Metal Halide Perovskite ◽  
Bonding Interaction ◽  
Halide Perovskites ◽  
Halide Perovskite ◽  
Low X

Abstract Metal halide perovskites have recently been reported as excellent scintillators for X-ray detection. However, perovskite based scintillators are susceptible to moisture and oxygen atmosphere, such as the water solubility of CsPbBr3, and oxidation vulnerability of Sn2+, Cu+. The traditional metal halide scintillators (NaI: Tl, LaBr3, etc.) are also severely restricted by their high hygroscopicity. Here we report a new kind of lead free perovskite with excellent water and radiation stability, Rb2Sn1-x Te x Cl6. The equivalent doping of Te could break the in-phase bonding interaction between neighboring octahedra in Rb2SnCl6, and thus decrease the electron and hole dimensionality. The optimized Te content of 5% resulted in high photoluminescence quantum yield of 92.4%, and low X-ray detection limit of 0.7 µGyair s−1. The photoluminescence and radioluminescence could be maintained without any loss when immersing in water or after 480,000 Gy radiations, outperforming previous perovskite and traditional metal halides scintillators.

Quantitative Evaluation of Voids in Lead Free Solder Joints

2015 ◽  
Vol 772 ◽  
pp. 284-289 ◽  
Author(s):  
Sabuj Mallik ◽  
Jude Njoku ◽  
Gabriel Takyi
Keyword(s):  
Solder Bump ◽  
Solder Joints ◽  
Void Formation ◽  
Lead Free ◽  
Lead Free Solder ◽  
Solder Paste ◽  
X Ray ◽  
Size And Shape ◽  
Solder Bumps ◽  
Free Solder

Voiding in solder joints poses a serious reliability concern for electronic products. The aim of this research was to quantify the void formation in lead-free solder joints through X-ray inspections. Experiments were designed to investigate how void formation is affected by solder bump size and shape, differences in reflow time and temperature, and differences in solder paste formulation. Four different lead-free solder paste samples were used to produce solder bumps on a number of test boards, using surface mount reflow soldering process. Using an advanced X-ray inspection system void percentages were measured for three different size and shape solder bumps. Results indicate that the voiding in solder joint is strongly influenced by solder bump size and shape, with voids found to have increased when bump size decreased. A longer soaking period during reflow stage has negatively affectedsolder voids. Voiding was also accelerated with smaller solder particles in solder paste.

Morphology and Intermetallic Study of (Sn-8Zn-3Bi)-1Ni Solder under Liquid State Aging

2015 ◽  
Vol 1087 ◽  
pp. 162-166
Author(s):  
Nor Aishah Jasli ◽  
Hamidi Abd Hamid ◽  
Ramani Mayappan
Keyword(s):  
Liquid State ◽  
Copper Substrate ◽  
Lead Free ◽  
Lead Free Solder ◽  
Reflow Time ◽  
Intermetallic Formation ◽  
X Ray ◽  
Ni Addition ◽  
Free Solder ◽  
Scanning Electron

This study investigated the effect of Ni addition on intermetallic formation in the Sn-8Zn-3Bi solder under liquid state aging. The intermetallic compounds were formed by reacting the solder alloy with copper substrate. Different reflow time was used at temperature 220°C. Morphology of the phases formed was observed using scanning electron microscope (SEM) and in order to determine elemental compositions of the phases, energy dispersive x-ray (EDX) was used. The formation of the reaction layer led by Cu5Zn8 intermetallic and then followed by Cu6Sn5 and Cu3Sn when reflow time increases. Keywords: lead free solder, intermetallic, Cu5Zn8, Cu6Sn5, liquid state aging.

Evaluation of Degradation Causes of the Forged Rotors Made of NiCrMo Steel Grade

2014 ◽  
Vol 782 ◽  
pp. 227-230
Author(s):  
Petr Jonšta ◽  
Roman Heide ◽  
Irena Vlčková ◽  
Miriam Gabčová ◽  
Zdenĕk Jonšta ◽  
...  
Keyword(s):  
Steel Grade ◽  
Excessive Amount ◽  
Steam Turbines ◽  
Electron Microscopic ◽  
X Ray ◽  
Metallic Inclusions ◽  
Casting Ladle ◽  
Nicrmov Steel

Contamination of steel by excessive amount of non metallic inclusions leads tosignificant deterioration of its quality and consequent degradation. Cause of degradation of forgedrotors for steam turbines made of NiCrMoV steel grade is examined in this paper. Metallographicand electron-microscopic analyses were performed, including X-ray microanalysis for detecting thepurity of the forging being examinated. Concurrently, the consequence of failed technologicalproduction process, namely the influence of broken brick for argon blowing at the casting ladle, wasalso examined.

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