Also, get a free upgrade to color casing and a 512mb independent graphics card, as well as other service upgrades.
更可免费升级彩壳和512 MB独显，服务升级等惊喜。
2
However, the API oil casing results in early damage during service, which causes premature discard of oil field, bringing big economic loss.
但在使用中api套管过早损坏，导致油井提前报废，给油田造成较大的经济损失。
3
Oilgas outputs, injection effectiveness and service life of production and injection well are directly affected by casing deformation and damages, such as outside force, chemical corrosion and so on.