... important equipment in oil field. Liande can provide sucker rods including grade C, K, D, KD, HL, HY and KH. ... Among them, grade C, K, D sucker rods are designed ... is not susceptible to sulphuric stress cracking. Grade D sucker rod is made from fine alloy steel, ... having the same size and main parameter as grade D sucker rod, but their strength is capable to ...