China's lone Golf class ballistic missile sub has apparently been refurbished, rather than scrapped. These diesel electric boats (SSGs) were introduced by Russia in the late 1950s, and 23 were built by the early 1960s, when attention was turned to nuclear ballistic missile boats (SSBN).
Fourteen Golfs were modified in 1966-72 to carry larger R-21 (1600 kilometer range) missiles. These boats remained in commission until 1990. A few years later, ten were sold to North Korea for scrap. It's not certain that North Korea actually dismantled all these subs. The North Korean No-Dong missiles was based on the R-21.
China received two Golf boats, seven R-11F missiles (a 300 kilometer range SCUD) and the building plans, from Russia in the 1960s, and the Chinese built one in the 1970s, as the JL-2. This boat rarely put to sea. The R-11F was the basis of later Chinese ballistic missile design. The recent refurbishment of the Chinese Golf apparently included changes to the three missile silos so the boat could be used to test new submarine launched ballistic missiles (SLBM).
The Golf was a 2,800 ton boat with a crew of 83 and three missile silos. There were also six torpedo tubes, and during the Cold War, these boats carried two torpedoes with nuclear warheads.