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
But he was not hitting her hard enough. He couldn't. Andshe was giggling52 at him. Spread-eagled on the floor,her brocaded gown hitched53 up above her thighs54,she taunted55 him between giggles56. "Come on, stickit in. Stick it in, Johnny, that's what you really want."
Johnny Fontane got up. He hated the woman on the floor buther beauty was a magic shield. Margot rolled away, and in adancer's spring was on her feet facing him. She went into achildish mocking dance and chanted, "Johnny never hurt me, Johnnynever hurt me." Then almost sadly with grave beauty she said, "Youpoor silly bastard57, giving me cramps58 like a kid.Ah, Johnny, you always will be a dumb romantic guinea, you evenmake love like a kid. You still think screwing is really like thosedopey songs you used to sing." She shook her head and said, "PoorJohnny. Goodbye, Johnny." She walked into the bedroom and he heardher turn the key in the lock.