热力管线中不锈钢波纹管破裂原因分析

采用金相显微镜和扫描电镜分析了热力管线中不锈钢 波纹管破裂原因.该波纹管破裂特征与一般环向开裂不同，裂纹沿轴向扩展.分析认为，破裂 属穿晶应力腐蚀.引起应力腐蚀的介质是土壤中的氯化物，而应力则来自环向工作应力和冷 加工残余应力，而环向工作应力起主导作用。     

水玻璃加入量对微波硬化砂强度及溃散性影响的试验研究

采用微波加热技术来加热硬化水玻璃砂,对比分析了水玻璃的加入量对砂型试样抗拉强度和残留强度的影响规律。试验结果表明,在539W微波功率加热条件下,水玻璃砂的抗拉强度随着水玻璃加入量的增加而强度上升;在相同微波加热条件下,水玻璃砂的残留强度也随着水玻璃加入量的增多而增大。     

高频感应熔覆Ni60合金粉末涂层的研究

研究了用3种方法制备的Ni60合金粉末涂层的显微组织和腐蚀特性，其中用第1种冷涂法制备预涂层，再经高频感应熔覆的方法比用第2种氧—乙炔喷涂法制备预涂层，然后用高频感应熔覆的方法经济实用。这两种方法所制备的涂层性能接近，组织均匀细致，有丰富的增强耐磨性的硬质相，显微结构和抗腐蚀性明显优于第3种用氧—乙炔喷焊制备的涂层。总之，冷预涂加高频熔覆法优于氧—乙炔预涂加高频熔覆法，高频感应熔覆法优于氧—乙炔喷焊法。     

The Microstructure and Mechanical Properties of the Low Carbon Microalloy Steel by High Voltage Electropulse Heating

The low carbon microalloy steel samples were heated to different temperatures by high voltage electropulse discharge heating method. The temperature of sample increases with the discharge current density. Microstructures were observed by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results show that coexist microstructure of ultrafine ferrite grain and martensite can be obtained by proper high voltage electropulse discharge heating process parameter. The tensile testing indicate that better mechanical properties were obtained, including 758MPa yield strength, 796MPa ultimate strength and 12% total elongation.     

浅析我国热处理设备的更新换代

低真空变压热处理技术（包括设备和工艺）是综合低真空热处理和变压热处理的优点的专利技术。该技术的炉气能快速吐故纳新和精确调控,其炉温也能精确控制,且与真空热处理炉相比,其设备的价格也较低廉,是“老三炉”更新换代的理想产品。广泛采用低真空变压热处理技术是缩短我国同发达国家之间差距的捷径之一。     

Advances in fabricating superplastically formed and diffusion bonded components for aerospace structures

Superplastic forming and diffusion bonding (SPF/DB) production hardware is being fabricated today for aerospace applications. Metal tooling is being used to bring the titanium sheets into contact so diffusion bonding can occur. However, due to material sheet and tooling tolerances, good bond quality is difficult to achieve over large areas. A better method for achieving DB is to use “stop-off” inside sealed sheets of titanium, which constitutes a pack, and then the pack is bonded using external gas pressure. A good method for heating the pack for this process is to use induction heating. Components using “stop-off” that were diffusion bonded first and then superplastically formed have shown much better bond quality than components that were produced using matched metal tooling. This type of tooling has been successful at bonding small areas as long as the exerted pressure is concentrated on the area where bonding is required. Finite element modeling is providing weight effect solutions for titanium SPF/DB aerospace structures. This paper was presented at the International Symposium on Superplasticity and Superplastic Forming, sponsored by the Manufacturing Critical Sector at the ASM International AeroMat 2004 Conference and Exposition, June 8–9, 2004, in Seattle, WA. The symposium was organized by Daniel G. Sanders, The Boeing Company.     

研究Nd-Fe-B粉末材料中不同状态氧的新方法

基于不同氧化物与碳的结合能不同,与碳的还原反应在不同的分析条件下具有先后次序,用脉冲红外氧化物夹杂分析仪,对4μm的烧结Nd Fe B永磁材料粉末的氧化行为进行了方法研究。实验结果表明,通过合理设置参数,选用跟踪升温模式,可以快速分离Nd Fe B永磁材料粉末中的不同氧化物,并可以通过加权方法进行定性验证。     

THERMOGRAPHIC ASPECT ON LOADING A THIN-WALL PRESSURE VESSEL STEEL

The infrared emission of a high pressure vessel steel and two thin wall pressure vessel modelshave been investigated by use of vibro-thermography.The experimental infrared cracklengths were found to be agreed closely with the optical values during fatigue process.A possi-ble nondestructive testing method used to evaluate the pressure vessel has been given.     

奥氏体化温度及冷却方式对20Mn2SiVB钢组织及性能的影响

通过各种试验手段,研究了20Mn2SiVB钢不同奥氏体化温度及不同冷却方式处理后其显微组织及其强度和塑性的变化,确定了最佳的热处理工艺。结果表明:900℃奥氏体化后风冷时钢的强塑性最好;在强塑性最佳时的微观组织是铁素体+粒状贝氏体。     

纳米晶软磁薄膜Fe-Ti-N的结构、磁学性能和热稳定性研究

在高溅射功率900W下用RF磁控溅射方法制备了厚为630－780nm的e-Ti-N薄膜。结果表明：当膜成分（原子分数，％，下同）在Fe-3.9Ti-8.8N和Fe-3.3Ti-13.5N范围内，薄膜由α′和Ti2N沉淀组成，磁化强度4πMs超过纯铁，最高可达2.38T；而矫顽力Hc下降为89A／m，可以满足针对1.55Gb/cm^2高存储密度的GMR／感应式复合读写磁头中写入磁头的需要，N原子进入α-Fe使α′具有高饱和磁化强度；Ti的加入，阻止α′→α γ′的分解，稳定了强铁磁性相α′，是Fe-Ti-N具有高饱和磁化强度的原因。由于由晶粒度引起的对Hc的影响程度Hc^D与晶粒度D有以下关系：Hc^D∝D^6，晶粒度控制非常重要。N原子进入α-Fe点阵的八面体间隙，引起极大的畸变，使晶粒碎化。提高溅射功率也使晶粒度下降。两者共同作用，能使晶粒度下降到约14nm，使Hc下降。晶界是择优沉淀地点，在α′晶界上沉淀Ti2N能起钉扎作用，阻止晶界迁移，使纳米晶α′不能长大。薄膜的结构和Hc的稳定温度不低于520℃。