現(xiàn)在隨著井蓋的盛行，然而在市面，它的種類也越來愈多，鑄鐵井蓋、球墨鑄鐵井蓋、復合井蓋、混凝土井蓋。其中鑄鐵井蓋與球墨鑄鐵井蓋外表很相似，單單從表面上看是無法辨別出來的，其實不同的材質(zhì)之間所表達出來的效果是不一樣的，那么這就需要我們在選購上能夠明確幾點重要的辨別事項。

Now with the popularity of manhole covers, however, in the market, there are more and more kinds of them, such as cast iron manhole covers, ductile iron manhole covers, composite manhole covers and concrete manhole covers. Among them, the appearance of cast iron manhole cover and ductile iron manhole cover is very similar, which can't be distinguished only from the surface. In fact, the effect expressed by different materials is different, so we need to be able to identify several important matters in the purchase.

（1）敲擊井蓋：球墨鑄鐵井蓋發(fā)出的生音似敲擊碳鋼的聲音?；诣F井蓋的敲擊聲音聽起來很悶。

(1) Knock well cover: the sound of ductile iron well cover is similar to that of carbon steel. The knock of the gray iron manhole cover sounds dull.

（2）從斷口處察看：前者的斷口晶粒很細小，為黑灰色。而灰鐵井蓋的斷口處晶粒比較粗大，為灰白色。

(2) From the fracture, the grains of the former are very fine and black gray. The grain size at the fracture of gray iron well cover is coarse and gray white.

（3）從治煉辦法來說：球墨鑄鐵井蓋是在治煉時在灰鐵中加孕育劑與球化劑使石墨有分散的團絮狀變成球狀，以減小對鐵素體的割裂，加大強度，提高性能來達到的。

(3) In terms of refining methods: nodular cast iron well cover is achieved by adding inoculant and nodularizing agent in gray iron during refining to make graphite have dispersed flocculent and turn into ball, so as to reduce the fracture of ferrite, increase strength and improve performance.

（4）灰鐵井蓋在治煉時不添加任何輔助材料，直接將生鐵治煉成鐵水，然后澆鑄成井蓋。前者在治煉時要加入球化劑、稀土鎂等金屬合金而成。

(4) The gray iron well cover is directly refined into molten iron without adding any auxiliary materials, and then cast into well cover. The former is made by adding spheroidizing agent, rare earth magnesium and other metal alloys.

（5）球墨鑄鐵井蓋強度高、韌性好、因而它比同類灰鐵井蓋輕30%左右。

(5) The ductile iron well cover has high strength and good toughness, so it is about 30% lighter than the similar gray iron well cover.

（6）同樣是球墨鑄鐵產(chǎn)品，球化率不同，質(zhì)量也就不同，價錢上也有很大區(qū)別。

(6) The same is ductile iron products, spheroidization rate is different, the quality is different, the price is also very different.