Hot Rolled 18Crnimo7-6 Equivalent 1.6587 18NCD6 Alloy Steel Round Bar 105MM

The failure cause of the 18CrNi3Mo steel for drilling bit, including inclusions, prior austenite grain size, carburized layers, and morphology of the fatigue fracture, was investigated by optical microscope, quantitative metallography, and scanning electron microscope. Results show that the failure of the drill bit is not related to interior inclusions or the inhomogeneity of the prior austenite grain size distribution. The failure is related to geometrical discontinuities causing stress concentration along the tooth profiles while under effect of continuous twisting and axial impact. Thus, the crack initiates in these areas, and the microstructures of the carburized layer, the transitive layer, and the matrix are all tempered martensite such that the crack propagation cannot be effectively restrained and the crack propagates quickly, causing premature failure of the drilling bit.

FAQ
1) why you chose us ?
Because we have large stocks and we have long term cooperative factories. We can get the lowest ex-factory prices. The price are quite reasonable and it is lower than our commercial peers. Also, we can guarantee the quality of our products.
2) Our minimum order quantity:
15 Metric Tons
3) How about the Delivery Time?
The steel pipe will be produced since we getting your deposit by T/T or original L/C, and delivery to the port of loading within 25~30 days.
For normal size, some stocks in our factory now, we can shipment within 7~10 days after receive the deposit.
4) What kind of payment does your company support?
T/T, 100% L/C at sight.
5) Do you charge for the samples?
No, we provide samples free, you pay for the freight charge.
6) Main market:
Mid East South America South Asia Africa Southeast Asia Northern Europe Western Europe etc.


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