我国首部锂离子电池安全国家标准发布

国家标准委发布《便携式电子产品用锂离子电池和电池组安全要求》(GB31241-2014)国家标准公告,并在强制性国家标准公开专栏公布了标准全文。该标准将于2015年8月1日起实施。     

电阻焊机安全要求标准和电气安全标准编制

论述了强制性国家标准GB 15578-2008《电阻焊机的安全要求》编制经过和特点,以及该标准涉及电气安全重要条款设置的原则和内容,提出了编制电气安全标准的一些具体要求。     

2014版GB/T 5613与GB/T 14408标准的主要变化

2014年批准发布的GB/T 5613—2014《铸钢牌号表示方法》和GB/T 14408—2014《一般工程与结构用低合金钢铸件》与旧标准相比有较大变化。文中根据新版国家标准,对其变化较大的内容进行介绍,并与旧标准进行分析比较,以便使用者在实际生产、教学、科研中更加深刻地理解和运用新标准。     

普通磨具行业近两年需完成修订的标准情况介绍

根据国家标准化管理委员会下达的磨料磨具标准制修订计划，普通磨具行业近两年需要修订的国家标准有十项。其中2005年度下达的普通磨具标准修订项目有七项，主要是采用ISO603：1999“固结磨具一尺寸系列”国际标准，代替GB／T4127—1997《普通磨具形状和尺寸》。2006年度下达的普通磨具标准修订项目有三项，主要是为了便于用户使用，将原有的八项国家标准进行帮合修订。现简要介绍如下：     

固结磨具用磨料粒度组成及其检测方法新标准介绍

１前言磨料粒度组成是磨料的重要质量技术指标，普通磨料按用途分固结磨具用和涂附磨具用两大类。固结磨具用磨料粒度组成及其检测方法新国家标准已于１９９８年１１月１８日发布，并于１９９９年９月１日起实施。新标准代替原ＧＢ２４７７—８３《磨料粒度及其组成》和Ｇ...     

GB/T6614-2014和GB/T15073-2014标准的主要变化

2014年修订发布的GB/T 6614-2014《钛及钛合金铸件》和GB/T 15703-2014《铸造钛及钛合金》与旧标准相比有较大变化。根据这两个新版国家标准,对其变化较大的内容进行介绍,并与旧标准进行分析比较,其目的在于使用者更好地理解、宣传和贯彻新标准。     

GB 15735—2012《金属热处理生产过程安全、卫生要求》的主要变化

<正>GB 15735—2012《金属热处理生产过程安全、卫生要求》强制性国家标准于2012年11月5日发布,2013年6月实施,实施后代替原2004年版标准。该标准由江苏丰东热技术股份有限公司、北京机电研究所等单位起草。该标准规定了热处理生产过程中安     

灰铸铁分级

国家标准局已颁布了新的灰铸铁分级(GB5675-85)标准,并已正式实施,新标准颁布实施后,GB976-67《灰铸铁分类及技术条件》中1、2、9、10、11条和附录等条款将同时作废.为了使广大铸造工作者在实际工作中更好地贯彻实施GB5675-85标准,本刊编辑部特该标准介绍如下:     

最新焊条国家标准修订情况概述

GB/T 5117—2012《非合金钢及细晶粒钢焊条》、GB/T 5118—2012《热强钢焊条》和GB/T 983—2012《不锈钢焊条》于2012年11月5日发布,2013年3月1日正式实施。新修订的这3个标准与旧标准相比变化较大。本文根据最新的国家标准对其变化较大的内容进行介绍,并与旧标准进行分析比较,其目的在于让使用者能更好地理解、宣传和贯彻新标准。     

GB/T 37681—2019《大型铸钢件通用技术规范》标准解读

阐述GB/T 37681—2019《大型铸钢件通用技术规范》标准技术要求、检验规则及试验方法等方面内容的要求和依据,并根据标准的内容论述新标准与国外相关标准的对比情况。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.