http://www.globalsecurity.org/military/world/china/jiangwei.htm
At least one if not as many as four of these ships were laid down for Pakistan's Navy to replace four US warships. Purchase of four of the ships was deferred in 1995 due to economic and diplomatic problems. The first unit was reportedly built for Pakistani Navy (numbered 597), but when budgetary constraints terminated the deal the ship was later renumbered as 521.
The F22-P [P for Pakistan] class frigates are the export version of the Jiangwei-II Type 053H2, built by China between 1996 and 2005. The Chinese version carries a pair of quadruple YJ-8II SSM systems and an octuple HQ-7 SAM system. While the hull and the main machinery of the Pakistani ships are expected to be the same as China's, the command-and-control systems,
the weapons, and the sensors were specially modified to Pakistan’s requirements. The ships were equipped with Pakistan's existing inventory of naval weapons: French Exocet, Chinese C-802, and US Harpoon Missiles. The F-22s will also had better ASW capability than the ex-Leanders.
The C28A-class corvette, was designed by the Marine Design and Research Institute under China State Shipbuilding Corp. In 2011, it defeated 10 competitors from eight countries for the Algerian Navy contract for three corvettes. The first C28A was delivered in September 2015 and the second in January 2016.
The C28A-class corvette represents the highest technological level of China's export warship, China Ship News quoted shipbuilding sources as saying in July 2016 that it has the best combat capability and is very competitive on the international market. With a displacement of 3,000 metric tons, the 120-meter-long corvette can conduct offshore defense operations and long-distance combat tasks. It is larger than previous warships China has sold to foreign nations, has new equipment, a stealth design and a higher level of automation. It has a cruise speed of about 30 km/h and an operational range of nearly 10,000 km.
Wu Qiang, general manager of China State Shipbuilding Corp, the parent company of the Hudong-Zhonghua, told China National Radio at the commissioning ceremony that the ship is a symbol of China's achievement. "In the past, naval ships we sold to other countries mostly used foreign-developed weapons, but all of the weapons and radar installed on three C28As, including anti-ship and anti-aircraft missiles, torpedoes and naval guns, are domestically developed," he said. "The results of these C28A ships' tests are very satisfactory, and our clients are happy with their performance."
Ren Yi, chief designer of the C28A, was quoted by China Central Television as saying that the ship can perform reconnaissance, aircraft and missile defense, anti-ship and anti-submarine operations, as well as maritime humanitarian missions. Gao Zhuo, a military observer in Beijing, told China Daily that China's new-generation naval vessels are reliable, have outstanding combat capabilities and are attractive in terms of price and operational costs, making them good choices for developing nations.
Jiangwei-III Type 053H2 [059?]
The last three vessels, Xiangfan (567), Luoyang (527) and Mianyang (528), have slightly different weapons and radar configuration. As the Jiangwei-II lacked vertical-launch system air defense missiles, they are being succeeded by the Jiangwei-III Type 059, to be built with VLS missiles. The Jiangwei-III Type 053H3 [seemingly not 059] class frigates was expected to begin construction before 2005. This anticipated to remedy the anti-air deficiencies of the Type 055 class through the addition of a vertical launch system battery of surface-to-air missiles. Construction of this third variant had apparently been abandoned in favor of the Type 054 Maanshan, similar to Jiangwei III except stealthy features and CIWS.
But Bernard D. Cole, author of "The Great Wall at Sea: China's Navy in the Twenty-First Century" visited a Jiangwei III–class FFG in May 2006, during which the ship's commanding officer described his ship, then just six months in commission, as a “Jiangwei III”. The Jiangwei III, of which at least one was in commission as of 2010, seemed to differ from its earlier models mainly in its improved command and control capabilities.