Vishnu’s sudarshana.

Surya married Vishwakarma’s daughter Samjna. She couldn’t stand his heat and their domestic life was not a happy one. She once requested her father to reduce his heat and he used the Shanopalayantra to do so. But that only reduced it by one eighth. This 1/8th fell towards the earth and with that Vishwakarma was able to make the chakra, a trident, the Pushpak and a weapon named Shakti. The trident went to Shiva, the Pushpak to Kuber and Shakti to Brahma. The most radiant chakra was dropped into the ocean as per Vishnupurana Chapter 3 verse 2.

Once when Krishna and Arjuna were relaxing on the banks of the Yamuna, Agni asked for their help in consuming the Khandava forest. Since Indra’s friend Thakshaka lived there, Indra made it rain whenever Agni tried to consume it. But they didn’t have sufficient weapons, so Agni prayed to Varuna, who gave Arjuna the Chandradhanus (Gandiva), a quiver with unlimited arrows, a chariot with a monkey on the flag, and to Krishna, the chakra. He also gave Arjuna four white horses. It was thus that the Chakra became Vishnu’s weapon as per Mahabharata Adiparva Chapter 237.