聚甲醛塑料，俗称赛钢，为结晶性热可塑性塑料，具明显熔点165~175℃，性质Zui接近金属。
优点 1、具高机械强度和刚性
2、Zui高的疲劳强度
3、环境抵抗性、耐有机溶剂性佳
4、耐反覆冲击性强
5、广泛的使用温度范围(-40℃~120℃)
6、良好的电气性质
7、复原性良好
8、具自已润滑性、耐磨性良好
9、尺寸安定性优
缺点 1、加工过程若长时间高温下易起热分解
2、无自熄性
3、抗酸性差
4、成形收缩率大
用途 电子电器：洗衣机、果汁机零件、定时器组件
汽 车： 车把零件、电动窗零件
工业零件：机械零件、齿轮、把手、玩具、螺杆
George scowled9 and looked sulky at once. Julianlaughed and slapped her on the shoulder. 'Whatalovely scowl10! One of your best! I haven't seen it for quitea long time. Keep it up, George - go on,scowl a bit harder, itsuits you!'
George grinned unwillingly11, and pulled herself together. Shehated being left out of anything -but she did see that it was nouse having a crowd of people watching that night. All right - shewouldstay with Anne and keep her company.
It seemed as if the watcher on the hills must have gone, becausethere were no more sudden flashessuch as came when he lifted hisfield-glasses to watch the Five.
'That disguised country-woman has convinced the watcher that we'regoing! Any ideas, anyone,where we can go? Not too far away - butsomewhere where the watcher can't follow us with hisglasses, ifhe's still up there.'